import java.util.*; import java.io.*; import java.math.*;
public class Main{
	//Don't have to see. start------------------------------------------
	static class InputIterator{
		ArrayList<String> inputLine = new ArrayList<>(1024);
		int index = 0; int max; String read;
		InputIterator(){
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			try{
				while((read = br.readLine()) != null){
					inputLine.addAll(Arrays.asList(read.split(" ")));
				}
			}catch(IOException e){}
			max = inputLine.size();
		}
		boolean hasNext(){return (index < max);}
		String next(){
			if(hasNext()){
				return inputLine.get(index++);
			}else{
				throw new IndexOutOfBoundsException("There is no more input");
			}
		}
	}
	static HashMap<Integer, String> CONVSTR = new HashMap<>();
	static InputIterator ii = new InputIterator();//This class cannot be used in reactive problem.
	static PrintWriter out = new PrintWriter(System.out);
	static void flush(){out.flush();}
	static void myout(Object t){out.println(t);}
	static void myerr(Object t){System.err.print("debug:");System.err.println(t);}
	static String next(){return ii.next();}
	static boolean hasNext(){return ii.hasNext();}
	static int nextInt(){return Integer.parseInt(next());}
	static long nextLong(){return Long.parseLong(next());}
	static double nextDouble(){return Double.parseDouble(next());}
	static ArrayList<String> nextCharArray(){return myconv(next(), 0);}
	static ArrayList<String> nextStrArray(int size){
		ArrayList<String> ret = new ArrayList<>(size);
		for(int i = 0; i < size; i++){
			ret.add(next());
		}
		return ret;
	}
	static ArrayList<Integer> nextIntArray(int size){
		ArrayList<Integer> ret = new ArrayList<>(size);
		for(int i = 0; i < size; i++){
			ret.add(Integer.parseInt(next()));
		}
		return ret;
	}
	static ArrayList<Long> nextLongArray(int size){
		ArrayList<Long> ret = new ArrayList<>(size);
		for(int i = 0; i < size; i++){
			ret.add(Long.parseLong(next()));
		}
		return ret;
	}
	@SuppressWarnings("unchecked")
	static String myconv(Object list, int no){//only join
		String joinString = CONVSTR.get(no);
		if(list instanceof String[]){
			return String.join(joinString, (String[])list);
		}else if(list instanceof ArrayList){
			return String.join(joinString, (ArrayList)list);
		}else{
			throw new ClassCastException("Don't join");
		}
	}
	static ArrayList<String> myconv(String str, int no){//only split
		String splitString = CONVSTR.get(no);
		return new ArrayList<String>(Arrays.asList(str.split(splitString)));
	}
	public static void main(String[] args){
		CONVSTR.put(8, " "); CONVSTR.put(9, "\n"); CONVSTR.put(0, "");
		solve();flush();
	}
	//Don't have to see. end------------------------------------------

	static void solve(){//Here is the main function
      int N = nextInt();
      int M = nextInt();
      Node[] list = new Node[N];
      for(int i = 0; i < N; i++){
        list[i] = new Node();
      }
      for(int i = 0; i < M; i++){
        int A = nextInt() - 1;
        int B = nextInt() - 1;
        int C = nextInt();
        list[A].child.add(new Edge(B, C));
        list[B].child.add(new Edge(A, C));
      }
      for(int i = 0; i < N; i++){
        list[i].T = nextInt();
      }
      PriorityQueue<Q> pq = new PriorityQueue<>();
      pq.add(new Q(0, 0l, 0));
      while(pq.size() > 0){
        Q tmp = pq.poll();
        int now = tmp.nx;
        long cost = tmp.cost;
        int sumT = tmp.sumT;
        list[now].cost = Math.min(list[now].cost, cost);
        if(now == N - 1){
          continue;
        }
        ArrayList<Edge> child = list[now].child;
        for(int i = 0; i < child.size(); i++){
          Edge e = child.get(i);
          long nxCost = cost + list[now].T + (e.C / (sumT + list[now].T));
          if(list[e.to].cost > nxCost){
            pq.add(new Q(e.to, nxCost, sumT + list[now].T));
          }
        }
      }
      myout(list[N - 1].cost);
	}
	//Method addition frame start

static class Node{
  ArrayList<Edge> child = new ArrayList<>();
  long cost = 1l << 60;
  int T;
  Node(){}
}

static class Edge{
  int to;
  int C;
  Edge(int to, int C){
    this.to = to;
    this.C = C;
  }
}
  
static class Q implements Comparable<Q>{
  long cost;
  int nx;
  int sumT;
  Q(int nx, long cost, int sumT){
    this.nx = nx;
    this.cost = cost;
    this.sumT = sumT;
  }
  public int compareTo(Q ato){
    return Long.compare(this.cost, ato.cost);
  }
}
  
	//Method addition frame end
}