#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

const int N = 200010;

int p[N], d[N]; // d[x]存x点到根节点的距离
int n, m;

int find(int x)
{
    if (p[x] != x) 
    {
        int t = find(p[x]);
        d[x] += d[p[x]];
        p[x] = t;
    }
    return p[x];
}

int main()
{
    while (cin >> n >> m)
    {
        memset(p, 0, sizeof p);
        memset(d, 0, sizeof d);
        for (int i = 1; i <= n; i ++ ) p[i] = i;

        int res = 0;
        while (m -- )
        {
            int a, b, c;
            scanf("%d%d%d", &a, &b, &c);
            a -- ;
            int fa = find(a), fb = find(b);
            if (fa != fb)
            {
                p[fb] = fa;
                d[fb] = d[a] - d[b] + c;
            }
            else if (d[b] - d[a] != c)
                res ++ ;
        }
        cout << res << endl;
    }
    return 0;
}