import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Set;



	//@Japanese
	/* PriorityQueueは拡張for文で出すとsortされてない順番で出てくる
	 * longのbit演算は1L<<posに注意
	 * JOIはMLEが厳しい。最悪shortを使う。
	 * ArrayListはオートボクシングが遅いから、最悪自作listを使う
	 */

	/*略語
	 * 2-to, 4-for, 8-from
	 * -L -long(型), -P -素数Pを法とした余り
	 * a,b -任意の引数, n,m -自然数, p -素数
	 * pos -postition
	 * abs -絶対値
	 * min -minimum, max -maximum, ave -average
	 * div -divide
	 * pow -power(累乗)
	 * ceil -ceiling(天井関数)
	 * dt -data
	 * ln -length
	 * sc -scanner
	 * INF -INFINITY
	 * e97 -10E9+7=1000000007(prime often used)
	 */


	public class Main {
		public static void main(String[] args) throws Exception {

			FastScanner sc = new FastScanner();
			PrintWriter out = new PrintWriter(System.out);

			int n = sc.nexI();
			int m = sc.nexI();
			Graph g = Graph.make_Graph(n, m, sc);
			
			int[] ts = new int[n];
			sc.ai(ts);

			int[][] dp = new int[n][1002];	//おむすびjを食べ、街iから今にも行けるようになるまでかかる時間
			
			fill(dp,INF);
			
			dp[0][ts[0]]=ts[0];
			
			
			for(int j=ts[0]; j<1002; j++) {
				int s = 0, reload=n;
				
				while(s<n) {
					reload=n;
					for(int v=s; v<n; v++) {
						if(dp[v][j]==INF) continue;
						for(Edge e: g.get(v)) {
							int pnew = min(1001, j+ts[e.v2]);
							int tnew = dp[v][j]+(e.w/j)+ts[e.v2];
							
							if(dp[e.v2][pnew]<=tnew) continue;
							dp[e.v2][pnew] = tnew;
							
							if((pnew == j) && (tnew == dp[v][j]) && (e.v2<j)) reload = min(reload,e.v2);
						}
					}
					s = reload;
				}
			}
			
			System.out.println(minAll(dp[n-1]));
			
			
			out.flush();
			return;
		}


		static class Graph {	//@Japanese 重み付きグラフ
			private ArrayList<Node> dt = new ArrayList<>();
			Graph(int sz) {
				for(int i = 0; i < sz; i++) {
					Node node1 = new Node();
					dt.add(node1);
				}
			}
			public void add(int v8, int cnct2, int w) {
				dt.get(v8).add(new Edge(v8, cnct2, w));
			}
			public void add2(int v1, int v2, int w) {
				dt.get(v1).add(new Edge(v1, v2, w));
				dt.get(v2).add(new Edge(v2, v1, w));
			}
			public Set<Edge> get(int v) {
				return dt.get(v).getAll();
			}
			public int size() {
				return dt.size();
			}
			public int sizeOf(int v) {
				return dt.get(v).size();
			}
			public void clear() {
				for(int i = 0; i < dt.size(); i++) {
					dt.get(i).clear();
				}
			}
			public void clear(int v) {
				dt.get(v).clear();
			}
			private void add_v(Node v_new) {
				dt.add(v_new);
			}
			public void show2() {
				for (int i = 0; i < dt.size(); i++) {
					System.out.print(i+":");
					for(Edge e: dt.get(i).getAll()) {
						e.show2();
					}
					System.out.println();
				}
			}
			public static Graph make_Graph(int vn, int en, FastScanner sc) {
				Graph g = new Graph(vn);
				for(int i = 0; i < en; i++) {
					int s1 = sc.nexI() - 1;
					int g1 = sc.nexI() - 1;
					int w = sc.nexI();
					g.add2(s1, g1, w);
				}

				return g;
			}

		}
		static class Node { // 重みつきグラフの頂点
			private Set<Edge> next_vs = new HashSet<>();
			public void add(Edge cnct2) {
				next_vs.add(cnct2);
			}
			public Set<Edge> getAll() {
				return next_vs;
			}
			public int size() {
				return next_vs.size();
			}
			public void clear() {
				next_vs.clear();
			}
			public void addAll(Node list2add) {
				this.next_vs.addAll(list2add.next_vs);
			}
		}
		static class Edge {	//重み着きのグラフの辺
			int from=-1, v2=-1;
			int w;
			public Edge(int going2, int weight_route) {
				this.v2 = going2;
				this.w = weight_route;
			}
			public Edge(int come8, int going2, int weight_route) {
				this.from = come8;
				this.v2 = going2;
				this.w = weight_route;
			}
			public void show2() {
				System.out.println(this.from +"->"+this.v2+" :w="+this.w);
			}
		}

		static class CompEdge_float implements Comparator<Edge>{
			//今は小さいのが前に出てくる
			public int compare(Edge a, Edge b) {
				if(a.w>b.w) return 1;
				else if(a.w<b.w) return -1;
				else return a.v2-b.v2;
			}
		}





		private static final int INF = (int) 1e8;
		private static final long INFL = (long) 1e17;
		private static final long e97 = 1000000007L;
		private static final long e99 =  998244353L;
		private static final double PI = Math.PI;

		private static void assertion(boolean should_true) {
			//throw Error if should_true is not true @Japanese「断言」
			if(!should_true) throw new AssertionError();
		}

		private static int abs(int a) {
			return (a>=0) ? a: -a;
		}
		private static long abs(long a) {
			return (a>=0) ? a: -a;
		}
		private static double abs(double a) {
			return (a>=0.0) ? a: -a;
		}

		private static int min(int a, int b) {
			return (a>b) ? b : a;
		}
		private static long min(long a, long b) {
			return (a>b) ? b : a;
		}
		private static double min(double a, double b) {
			return (a>b) ? b : a;
		}

		private static int max(int a, int b) {
			return (a>b) ? a : b;
		}
		private static long max(long a, long b) {
			return (a>b) ? a : b;
		}
		private static double max(double a, double b) {
			return (a>b) ? a : b;
		}


		private static int pow2(int num2pow) {
			return num2pow*num2pow;
		}
		private static long pow2(long num2pow) {
			return num2pow*num2pow;
		}


		private static int pow(int num_powered, int index) {
			int ans = 1;
			for(int i=0; i<index; i++) {
				ans *= num_powered;
				assertion(ans>=0);
			}
			return ans;
		}
		private static long pow(long num_powered, int index) {
			long ans = 1L;
			for(int i=0; i<index; i++) {
				ans *= num_powered;
				assertion(ans>=0L);
			}
			return ans;
		}
		private static long powP(long num_powered, long index, long p) {
			//@Japanese 繰り返し二乗法
			if(num_powered==0L) return 0L;
			if(index==0L) return 1L;
			if(index==2L) {
				long ans = num_powered*num_powered;
				assertion(ans>0);
				return ans%p;
			}

			int d = getDigit2(index);
			long[] num_done_by2 = new long[d+1];
			num_done_by2[0] = num_powered;
			for(int i=1; i<=d; i++) {
				num_done_by2[i] = num_done_by2[i-1]*num_done_by2[i-1];
				assertion(num_done_by2[i]>0);
				num_done_by2[i]%=p;
			}
			long ans=1L;
			for(int i=d; i>=0; i--) {
				if(index >= (1L<<(long)i)) {
					index -= (1L<<(long)i);
					ans = ans*num_done_by2[i];
					assertion(ans>0);
					ans %= p;
				}
	 		}
			return ans%p;
		}
		private static double hypod(double a, double b) {
			return Math.sqrt(a*a+b*b);
		}

		private static int getDigit2(long num2know) {
			long compare4 = 1L;
			int digit = 0;
			while(num2know > compare4) {
				digit ++;
				compare4 = (1L<<(long)digit);
			}
			return digit;
			 //num <= 2^digit
		}
		private static int getDigit10(long num2know) {
			long compare4 = 1L;
			int digit = 0;
			while(num2know >= compare4) {
				digit ++;
				compare4 *= 10L;
			}
			return digit;	//@Japanese num は digit桁の数で、10^digit未満

		}


		private static int divceil(int numerator, int denominator) {
			return (numerator+denominator-1)/denominator;
		}
		private static long divceil(long numerator, long denominator) {
			return (numerator+denominator-1L)/denominator;
		}


		private static long factorial(int n) {
			long ans=1L;
			for(long i=n; i>0; i--) {
				ans *= i;
				assertion(ans>=0L);
			}
			return ans;
		}
		private static long facP(int n, long p) {
			long ans=1L;
			for(long i=n; i>0; i--) {
				ans *= i;
				ans %= p;
			}
			return ans;
		}

		private static long lcm(long m, long n) {
			assertion((m>0L) && (n>0L));
			long ans = m/gcd(m,n);
			ans *= n;
			return ans;
		}
		private static long gcd(long m, long n) {
			//if(isINFL(-m)) return n;
			assertion((m>=0L) && (n>=0L));
			if(m < n) return gcd(n, m);
			if(n == 0) return m;
			return gcd(n, m % n);
		}

		private static boolean is_prime(long n2check) {
			if(n2check==1L) return false;
			for(long i=2L; i<=Math.sqrt(n2check); i++) {
				if(n2check%i == 0) return false;
			}
			return true;
		}

		private static long modinv(long n, long p) {
			assertion((n>0L)&&(p>1L)&&(gcd(n,p)==1L));
			n %= p;

			//@Japanese
			//a⊥p, >1に注意

			//yn≡1(mod p)
			//<-> xp+yn=1;	(n<p)
			//...(sx+ty)a+(ux+vy)b=1	(|sv-tu|=1)
			//...(sx+ty)a+(ux+vy)=1
			//<- sx+ty=0, ux+vy=1

			long a=p, b=n, s=1, t=0, u=0, v=1;
			while(b>1) {
				long quo = a/b;
				long rem = a%b;
				a=b; b=rem;
				long s2 = s*quo+u, t2=t*quo+v;
				u=s; v=t;
				s=s2; t=t2;
			}
			long det = s*v-t*u;
			assertion(abs(det)==1);
			s /= det;
			s %= p;
			if(s < 0L) s += p;
			return s;
		}

		private static int minAll(int[] dt4min) {
			int min = INF;
			for(int element: dt4min) {
				if(element < min) min = element;
			}
			return min;
		}
		private static long minAll(long[] dt4min) {
			long min = INFL;
			for(long element: dt4min) {
				if(element < min) min = element;
			}
			return min;
		}
		private static int maxAll(int[] dt4max) {
			int max = -INF;
			for(int element: dt4max) {
				if(element < max) max = element;
			}
			return max;
		}
		private static long maxAll(long[] dt4max) {
			long max = -INFL;
			for(long element: dt4max) {
				if(element < max) max = element;
			}
			return max;
		}

		private static int sumAll(int[] dt4sum) {
			int sum_of_dt = 0;
			for(int element: dt4sum) {
				sum_of_dt += element;
			}
			return sum_of_dt;
		}
		private static long sumAll(long[] dt4sum) {
			long sum_of_dt = 0L;
			for(long element: dt4sum) {
				sum_of_dt += element;
			}
			return sum_of_dt;
		}
		private static int sumAll(ArrayList<Integer> dt4sum) {
			int sum_of_dt = 0;
			for(long element: dt4sum) {
				sum_of_dt += element;
			}
			return sum_of_dt;
		}
		/*private static long sumAll(ArrayList<Long> dt4sum) {
			long sum_of_dt = 0L;
			for(long element: dt4sum) {
				sum_of_dt += element;
			}
			return sum_of_dt;
		}*/

		private static int[] reverse(int[] as) {
			int ln = as.length;
			int[] bs = new int[ln];
			for(int i=0; i<ln; i++) {
				bs[i] = as[ln-i-1];
			}
			return bs;
		}
		private static void reverseSub(int[] as, int S_include, int Gnot_include) {
			//Caution: O(n)
			int ln = Gnot_include-S_include;

			int[] bs = new int[ln];
			for(int i=S_include; i<Gnot_include; i++) {
				bs[i-S_include] = as[i];
			}
			for(int i=0; i<ln; i++) {
				as[i+S_include] = bs[ln-i-1];
			}
		}


		private static boolean is_in_area(int y, int x, int height, int width) {
			if(y < 0) return false;
			if(x < 0) return false;
			if(y >= height) return false;
			if(x >= width) return false;
			return true;
		}

		private static boolean is_in_area(Vector v, int height, int width) {
			if(v.y < 0) return false;
			if(v.x < 0) return false;
			if(v.y >= height) return false;
			if(v.x >= width) return false;
			return true;
		}


		private static int nC2(int n) {
			return ((n*(n-1))/2);
		}
		private static long nC2(long n) {
			return ((n*(n-1L))/2L);
		}


		private static int iflag(int pos) {
			assertion(pos<31);
			return (1<<pos);
		}
		private static long flag(int pos) {
			assertion(pos<63);
			return (1L<<(long)pos);
		}
		private static boolean isFlaged(int bit, int pos) {
			if((bit&(1<<pos)) > 0) return true;
			else return false;
		}
		private static boolean isFlaged(long bit, int pos) {
			if((bit&(1L<<(long)pos)) > 0L) return true;
			else return false;
		}
		private static int deflag(int bit, int pos) {
			return bit&~(1<<pos);
		}
		private static int countFlaged(int bit) {
			int ans=0;
			for(int i=0; i<31; i++) {
				if((bit&(1<<i)) > 0) ans++;
			}
			return ans;
		}
		private static int countFlaged(long bit) {
			int ans=0;
			for(long i=0; i<63L; i++) {
				if((bit&(1L<<i)) > 0) ans++;
			}
			return ans;
		}

		private static int[] Xdir4 = {1,0,0,-1};
		private static int[] Ydir4 = {0,1,-1,0};
		private static int[] Xdir8 = {1,1,1,0,0,-1,-1,-1};
		private static int[] Ydir8 = {1,0,-1,1,-1,1,0,-1};

		public static int biSearch(int[] dt, int target) {
			int left=0, right=dt.length-1;
			int mid=-1;
			while(left<=right) {
				mid = (right+left)/2;
				if(dt[mid] == target) return mid;
				if(dt[mid] < target) left=mid+1;
				else right=mid-1;
			}
			return -1;
		}

		public static int biSearchMax(long[] dt, long target) {
			int left=-1, right=dt.length, mid=-1;
			while((right-left)>1) {
				mid = (right+left)/2;
				if(dt[mid] <= target) left=mid;
				else right=mid;
			}
			return left;
			//@Japanese target以下の最大のaddress
		}
		public static int biSearchMin(long[] dt, long target) {
			int left=-1, right=dt.length, mid=-1;
			while((right-left)>1) {
				mid = (right+left)/2;
				if(dt[mid] <= target) left=mid;
				else right=mid;
			}
			return right;
			//@Japanese targetより大きい最小のaddress
		}


		private static void fill(boolean[] target, boolean reset) {
			for(int i=0; i<target.length; i++) target[i] = reset;
		}
		private static void fill(int[] target, int reset) {
			for(int i=0; i<target.length; i++) target[i] = reset;
		}
		private static void fill(long[] target, long reset) {
			for(int i=0; i<target.length; i++) target[i] = reset;
		}
		private static void fill(char[] target, char reset) {
			for(int i=0; i<target.length; i++) target[i] = reset;
		}
		private static void fill(double[] target, double reset) {
			for(int i=0; i<target.length; i++) target[i] = reset;
		}

		private static void fill(boolean[][] target,boolean reset) {
			for(int i=0;i<target.length; i++) {
				for(int j=0; j<target[i].length; j++) {
					target[i][j] = reset;
				}
			}
		}
		private static void fill(int[][] target, int reset) {
			for(int i=0; i<target.length; i++) {
				for(int j=0; j<target[i].length; j++) {
					target[i][j] = reset;
				}
			}
		}
		private static void fill(long[][] target, long reset) {
			for(int i=0; i<target.length; i++) {
				for(int j=0; j<target[i].length; j++) {
					target[i][j] = reset;
				}
			}
		}
		private static void fill(char[][] target, char reset) {
			for(int i=0; i<target.length; i++) {
				for(int j=0; j<target[i].length; j++) {
					target[i][j] = reset;
				}
			}
		}
		private static void fill(double[][] target, double reset) {
			for(int i=0; i<target.length; i++) {
				for(int j=0; j<target[i].length; j++) {
					target[i][j] = reset;
				}
			}
		}
		private static void fill(int[][][] target,int reset) {
			for(int i=0;i<target.length;i++) {
				for(int j=0;j<target[i].length;j++) {
					for(int k=0;k<target[i][j].length;k++) {
						target[i][j][k]=reset;
					}
				}
			}
		}
		private static void fill(long[][][] target,long reset) {
			for(int i=0;i<target.length;i++) {
				for(int j=0;j<target[i].length;j++) {
					for(int k=0;k<target[i][j].length;k++) {
						target[i][j][k]=reset;
					}
				}
			}
		}

		private static void showBit(int bit) {
			for(int i=0; i<getDigit2(bit); i++) {
				if(isFlaged(bit,i)) System.out.print("O");
				else System.out.print(".");
			}
			System.out.println();
		}
		private static void showBit(long bit) {
			for(int i=0; i<getDigit2(bit); i++) {
				if(isFlaged(bit,i)) System.out.print("O");
				else System.out.print(".");
			}
			System.out.println();
		}
		static void show2(boolean[][] dt, String cmnt) {
			for(int i=0; i<dt.length; i++) {
				for(int j=0; j<dt[i].length; j++) {
					if(dt[i][j]) System.out.print("O");
					else System.out.print(".");
				}
				if(!cmnt.equals("")) System.out.print("<-"+cmnt);
				System.out.println(" :"+i);
			}
		}
		static void show2(int[][] dt, String cmnt) {
			for(int i=0; i<dt.length; i++) {
				for(int j=0; j<dt[i].length; j++) {
					System.out.print(dt[i][j]+",");
				}
				if(!cmnt.equals("")) System.out.print("<-"+cmnt);
				System.out.println(" :"+i);
			}
		}
		static void show2(long[][] dt, String cmnt) {
			for(int i=0; i<dt.length; i++) {
				for(int j=0; j<dt[i].length; j++) {
					System.out.print(dt[i][j]+",");
				}
				if(!cmnt.equals("")) System.out.print("<-"+cmnt);
				System.out.println(" :"+i);
			}
		}
		static void show2(ArrayDeque<Long> dt) {
			long element=0;
			while(dt.size()>0) {
				element=dt.removeFirst();
				System.out.print(element);
			}
			System.out.println("\n");
		}
		static void show2(List<Object> dt) {
		 	for(int i=0; i<dt.size(); i++) {
				System.out.print(dt.get(i)+",");
			}
			System.out.println("\n");
		}

		private static void prtlnas(int[] array) {
			PrintWriter out = new PrintWriter(System.out);
			for(int i=0; i<array.length; i++) {
				out.println(array[i]);
			}
			out.flush();
		}
		private static void prtlnas(long[] array) {
			PrintWriter out = new PrintWriter(System.out);
			for(int i=0; i<array.length; i++) {
				out.println(array[i]);
			}
			out.flush();
		}
		private static void prtlnas(ArrayList<Object> array) {
			PrintWriter out = new PrintWriter(System.out);
			for(int i=0; i<array.size(); i++) {
				out.println(array.get(i));
			}
			out.flush();
		}
		private static void prtspas(int[] array) {
			PrintWriter out = new PrintWriter(System.out);
			out.print(array[0]);
			for(int i=1; i<array.length; i++) {
				out.print(" "+array[i]);
			}
			out.println();
			out.flush();
		}
		private static void prtspas(long[] array) {
			PrintWriter out = new PrintWriter(System.out);
			out.print(array[0]);
			for(int i=1; i<array.length; i++) {
				out.print(" "+array[i]);
			}
			out.println();
			out.flush();
		}
		private static void prtspas(double[] array) {
			PrintWriter out = new PrintWriter(System.out);
			out.print(array[0]);
			for(int i=1; i<array.length; i++) {
				out.print(" "+array[i]);
			}
			out.println();
			out.flush();
		}
		private static void prtspas(ArrayList<Integer> array) {
			PrintWriter out = new PrintWriter(System.out);
			out.print(array.get(0));
			for(int i=1; i<array.size(); i++) {
				out.print(" "+array.get(i));
			}
			out.println();
			out.flush();
		}


		static class Vector {
			int x,y;
			public Vector(int sx, int sy) {
				this.x=sx;
				this.y=sy;
			}
		}

		static class FastScanner {
			private final InputStream in = System.in;
			private final byte[] buffer = new byte[1024];
			private int ptr = 0;
			private int buflen = 0;
			private boolean hasNextByte() {
				if(ptr < buflen) {
					return true;
				}else{
					ptr = 0;
					try {
						buflen = in.read(buffer);
					} catch (IOException e) {
						e.printStackTrace();
					}
					if(buflen <= 0) {
						return false;
					}
				}
				return true;
			}
			private int readByte() {
				if(hasNextByte()) return buffer[ptr++];
				else return -1;
			}
			private static boolean isPrintableChar(int c) {
				return (33 <= c) && (c <= 126);
			}
			public boolean hasNext() {
				while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
				return hasNextByte();
			}
			public String next() {
				if(!hasNext()) throw new NoSuchElementException();
				StringBuilder sb = new StringBuilder();
				int b = readByte();
				while(isPrintableChar(b)) {
					sb.appendCodePoint(b);
					b = readByte();
				}
				return sb.toString();
			}
			public long nexL() {
				if(!hasNext()) throw new NoSuchElementException();
				long n = 0;
				boolean minus = false;
				int b = readByte();
				if(b == '-') {
					minus = true;
					b = readByte();
				}
				if(b < '0' || '9' < b) {
					throw new NumberFormatException();
				}
				while(true) {
					if('0' <= b && b <= '9') {
						n *= 10;
						n += b - '0';
					}else if(b == -1 || !isPrintableChar(b) || b == ':') {
						return minus ? -n : n;
					}else{
						throw new NumberFormatException();
					}
					b = readByte();
				}
			}
			public int nexI() {
				long nl = nexL();
				if(nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) {
					throw new NumberFormatException();
				}
				return (int) nl;
			}
			public double nexD() { return Double.parseDouble(next());}
			//a means array
			public void ai(int[]... array) {
				for(int i=0; i<array[0].length; i++) {
					for(int j=0; j<array.length; j++) {
						array[j][i] = nexI();
					}
				}
				return;
			}
			public void al(long[]... array) {
				for(int i=0; i<array[0].length; i++) {
					for(int j=0; j<array.length; j++) {
						array[j][i] = nexL();
					}
				}
				return;
			}
			public void aimin1(int[] array) {
			 	for(int i=0; i<array.length; i++) {
			 		array[i] = nexI()-1;
			 	}
			 	return;
			}
			public void aD(double[] array) {
			 	for(int i=0; i<array.length; i++) {
			 		array[i] = nexD();
			 	}
			 	return;
			}
			public void ai2d(int[][] array) {
				for(int i=0; i<array.length; i++) {
					for(int j=0; j<array[0].length; j++) {
						array[i][j] = nexI();
					}
				}
				return;
			}
			public void al2d(long[][] array) {
				for(int i=0; i<array.length; i++) {
					for(int j=0; j<array[0].length; j++) {
						array[i][j] = nexL();
					}
				}
				return;
			}
		}
	}
	//END OF THE CODE