import java.io.*;
import java.lang.reflect.Array;
import java.util.*;
import java.util.Map.Entry;
import java.util.function.Function;
import java.util.stream.Collectors;

@SuppressWarnings("unused")
public class Main {
	FastScanner in = new FastScanner(System.in);
	PrintWriter out = new PrintWriter(System.out);
	
	long[] dist, num;
		
	//System.out.println();はつかわない！！
	void solve() throws Exception{
		int N = in.nextInt(), M = in.nextInt();
		long maxC = 0;
		ArrayList<ArrayList<Edge>> G = new ArrayList<>();
		for(int i = 0; i < N; i++) G.add(new ArrayList<>());
		for(int i = 0; i < M; i++){
			int a = in.nextInt()-1, b = in.nextInt()-1;
			long c = in.nextLong();
			maxC = Math.max(maxC, c);
			G.get(a).add(new Edge(a, b, c));
			G.get(b).add(new Edge(b, a, c));
		}
		for(int i = 0; i < N; i++) for(int j = 0; j < G.get(i).size(); j++) G.get(i).get(j).cost = maxC - G.get(i).get(j).cost;
		
		dist = new long[N]; num = new long[N];
		long max = 0;
		for(int s = 0; s < N; s++){
			dijkstra(G, s);
			for(int i = 0; i < N; i++){
				//out.println(num[i] + " " + (num[i] * maxC - dist[i]));
				if(dist[i] == Long.MAX_VALUE / 2) continue;
				max = Math.max(max, (num[i] * maxC - dist[i]));
			}
		}
		out.println(max);
	}
	
	long[] dijkstra(ArrayList<ArrayList<Edge>> G, int start){
		long INF = Long.MAX_VALUE / 2;
		Arrays.fill(dist, INF);
		Arrays.fill(num, 0);
		dist[start] = 0;
		PriorityQueue<Node> priorityQueue = new PriorityQueue<Node>();
		priorityQueue.add(new Node(start, 0, 0));
		
		while(!priorityQueue.isEmpty()){
			Node node = priorityQueue.poll();
			if(dist[node.index] < node.cost) continue;
			for(Edge e : G.get(node.index)){
				if(dist[e.to] > dist[node.index] + e.cost){
					dist[e.to] = dist[node.index] + e.cost;
					num[e.to] = node.num+1;
					priorityQueue.add(new Node(e.to, dist[e.to], node.num+1));
				}
			}
		}
		
		return dist;
	}
	
	class Node implements Comparable<Node>{
		int index, num;
		long cost;
		public Node(int i, long c, int n){
			index = i; cost = c; num = n;
		}
		@Override
		public int compareTo(Node o) {
			return Long.compare(this.cost, o.cost);
		}
	}

	class Edge implements Comparable<Edge>{
		int from;
		int to;
		long cost;
		public Edge(int f, int t, long c){
			from = f;to = t;cost = c;
		}
		@Override
		public int compareTo(Edge o) {
			return Long.compare(this.cost, o.cost);
		}
	}
		
	public static void main(String[] args) throws Exception {
		new Main().m();
	}
	
	void m() throws Exception {
		solve();
		out.flush();
	}
	
	class FastScanner {
		Reader input;

		FastScanner() {this(System.in);}
		FastScanner(InputStream stream) {this.input = new BufferedReader(new InputStreamReader(stream));}
		
		int nextInt() {return (int) nextLong();}

		long nextLong() {
			try {
				int sign = 1;
				int b = input.read();
				while ((b < '0' || '9' < b) && b != '-' && b != '+') {
					b = input.read();
				}
				if (b == '-') {
					sign = -1;
					b = input.read();
				} else if (b == '+') {
					b = input.read();
				}
				long ret = b - '0';
				while (true) {
					b = input.read();
					if (b < '0' || '9' < b) return ret * sign;
					ret *= 10;
					ret += b - '0';
				}
			} catch (IOException e) {
				e.printStackTrace();
				return -1;
			}
		}

		double nextDouble() {
			try {
				double sign = 1;
				int b = input.read();
				while ((b < '0' || '9' < b) && b != '-' && b != '+') {
					b = input.read();
				}
				if (b == '-') {
					sign = -1;
					b = input.read();
				} else if (b == '+') {
					b = input.read();
				}
				double ret = b - '0';
				while (true) {
					b = input.read();
					if (b < '0' || '9' < b) break;
					ret *= 10;
					ret += b - '0';
				}
				if (b != '.') return sign * ret;
				double div = 1;
				b = input.read();
				while ('0' <= b && b <= '9') {
					ret *= 10;
					ret += b - '0';
					div *= 10;
					b = input.read();
				}
				return sign * ret / div;
			} catch (IOException e) {
				e.printStackTrace();
				return Double.NaN;
			}
		}

		char nextChar() {
			try {
				int b = input.read();
				while (Character.isWhitespace(b)) {
					b = input.read();
				}
				return (char) b;
			} catch (IOException e) {
				e.printStackTrace();
				return 0;
			}
		}

		String nextStr() {
			try {
				StringBuilder sb = new StringBuilder();
				int b = input.read();
				while (Character.isWhitespace(b)) {
					b = input.read();
				}
				while (b != -1 && !Character.isWhitespace(b)) {
					sb.append((char) b);
					b = input.read();
				}
				return sb.toString();
			} catch (IOException e) {
				e.printStackTrace();
				return "";
			}
		}
		
		public int[] nextIntArray(int n) {
			int[] res = new int[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextInt();
			}
			return res;
		}
 
		public int[] nextIntArrayDec(int n) {
			int[] res = new int[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextInt() - 1;
			}
			return res;
		}
 
		public int[] nextIntArray1Index(int n) {
			int[] res = new int[n + 1];
			for (int i = 0; i < n; i++) {
				res[i + 1] = nextInt();
			}
			return res;
		}
 
		public long[] nextLongArray(int n) {
			long[] res = new long[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextLong();
			}
			return res;
		}
 
		public long[] nextLongArrayDec(int n) {
			long[] res = new long[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextLong() - 1;
			}
			return res;
		}
 
		public long[] nextLongArray1Index(int n) {
			long[] res = new long[n + 1];
			for (int i = 0; i < n; i++) {
				res[i + 1] = nextLong();
			}
			return res;
		}
 
		public double[] nextDoubleArray(int n) {
			double[] res = new double[n];
			for (int i = 0; i < n; i++) {
				res[i] = nextDouble();
			}
			return res;
		}
	}
}
/* end Main */