#include <bits/stdc++.h>

using namespace std;

const int NMax = 1e5 + 5;
const int INF = 2e9;

int n, ans;
int D[NMax], A[NMax];
bool Ciclu[NMax];

vector < pair < int, int > > G[NMax];
vector < int > Gi[NMax];

deque < int > Q;

inline void Bellman(const int &start){
    int node;
    Q.clear();
    Q.push_back(start);
    for(int i = 1; i <= n; i++){
        A[i] = INF;
    }
    A[start] = 0;
    while(!Q.empty()){
        node = Q.front(); Q.pop_front();
        for(auto it: G[node]){
            if(A[it.first] > A[node] + it.second){
                A[it.first] = A[node] + it.second;
                Q.push_back(it.first);
                D[it.first]++;
                if(D[it.first] > n){
                    Ciclu[it.first] = 1;
                    return;
                }
            }
        }
    }
}

bool viz[NMax];

inline void BFS(){
    int node;
    while(!Q.empty()){
        node = Q.front(); Q.pop_front();
        for(auto it: Gi[node]){
            if(!viz[it]){
                ans++;
                viz[it] = 1;
                Q.push_back(it);
            }
        }
    }
}

int main(){
    /*#ifndef ONLINE_JUDGE
    freopen("debug.in", "r", stdin);
    #endif // ONLINE_JUDGE*/

    freopen("a.in", "r", stdin);

    int m, a, b, c;
    cin >> n >> m;
    for(int i = 1; i <= m; i++){
        cin >> a >> b >> c;
        G[a].push_back({b, c});
        Gi[b].push_back(a);
    }
    for(int i = 1; i <= n; i++){
        if(D[i] == 0){
            Bellman(i);
        }
    }
    Q.clear();
    for(int i = 1; i <= n; i++){
        if(Ciclu[i]){
            ans++;
            viz[i] = 1;
            Q.push_back(i);
        }
    }
    BFS();
    cout << ans;
    return 0;
}