import java.io.*;
import java.util.*;

public class Main {

    static class Node {
	int to;
	int accval;
	boolean isDouble;

	Node(int t, int v, boolean i) {
	    to = t;
	    accval = v;
	    isDouble = i;
	}
    }

    public static void main(String[] args) throws Exception {
	//System.setIn(new FileInputStream("input.txt"));
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

	StringTokenizer st = new StringTokenizer(br.readLine(), " ");
	int N = Integer.parseInt(st.nextToken());
	int M = Integer.parseInt(st.nextToken());

	List<int[]>[] g = new ArrayList[N];
	for (int i = 0; i < N; i++) {
	    g[i] = new ArrayList<>();
	}

	int[] foxDist = new int[N];
	Arrays.fill(foxDist, Integer.MAX_VALUE);
	foxDist[0] = 0;

	for (int i = 0; i < M; i++) {
	    st = new StringTokenizer(br.readLine(), " ");
	    int a = Integer.parseInt(st.nextToken()) - 1;
	    int b = Integer.parseInt(st.nextToken()) - 1;
	    int d = Integer.parseInt(st.nextToken());
	    g[a].add(new int[] { b, d * 2 });
	    g[b].add(new int[] { a, d * 2 });
	}
	PriorityQueue<Node> pq = new PriorityQueue<>((o1, o2) -> {
	    return Integer.compare(o1.accval, o2.accval);
	});

	pq.offer(new Node(0, 0, false));

	while (!pq.isEmpty()) {
	    Node curr = pq.poll();

	    if (curr.accval > foxDist[curr.to])
		continue;

	    for (int[] near : g[curr.to]) {
		if (foxDist[near[0]] > foxDist[curr.to] + near[1]) {
		    foxDist[near[0]] = foxDist[curr.to] + near[1];
		    pq.offer(new Node(near[0], foxDist[near[0]], false));
		}
	    }
	}

	// 여우 처리 완료

	int[][] NodeDist = new int[2][N];
	Arrays.fill(NodeDist[0], Integer.MAX_VALUE);
	Arrays.fill(NodeDist[1], Integer.MAX_VALUE);

	NodeDist[1][0] = 0;

	pq.offer(new Node(0, 0, true)); // to accval isDouble

	while (!pq.isEmpty()) {
	    Node curr = pq.poll();

	    if (curr.accval > NodeDist[curr.isDouble ? 1 : 0][curr.to])
		continue;

	    for (int[] near : g[curr.to]) {
		if (curr.isDouble) {
		    int i = NodeDist[0][near[0]];
		    if (i > curr.accval + near[1] / 2) {
			NodeDist[0][near[0]] = curr.accval + near[1] / 2;

			pq.offer(new Node(near[0], NodeDist[0][near[0]], false));

		    }
		} else {
		    int i = NodeDist[1][near[0]];
		    if (i > curr.accval + near[1] * 2) {
			NodeDist[1][near[0]] = curr.accval + near[1] * 2;

			pq.offer(new Node(near[0], NodeDist[1][near[0]], true));
		    }

		}
	    }
	}
	int result = 0;

	for (int i = 0; i < N; i++) {
	    if (foxDist[i] < Math.min(NodeDist[0][i], NodeDist[1][i])) {
		result++;
	    }
	}
	System.out.print(result);

    }

}