#include <cstdio>

#include <algorithm>

using namespace std;

const int maxn = ;

int val[maxn],fa[maxn],n,m,ans=;//fa记录下标所能到达最左端(),val表示前缀和

void init(){

    for(int i=;i<=n;i++)

    {

        fa[i] = i;

        val[i]=;

    }

}

int find (int x)

{

    if(fa[x]==x)return x;

    else

    {

        int fn = find(fa[x]);

        val[x] +=val[fa[x]];

        return fa[x] = fn;

    }

}

void uni(int a,int b,int s)

{

    int px = find(a);

    int py = find(b);

    if(px==py)                //只有左区间相同是才能比较

    {

        if(val[b]-val[a]!=s)ans++;

    }

    else

    {

        fa[py] = px;

        val[py] = val[a] + s - val[b];

    }

}

int main(){

    while(~scanf("%d%d",&n,&m))

    {

        init();

        ans = ;

        for(int i=;i<=m;i++)

        {

            int a,b,s;

            scanf("%d%d%d",&a,&b,&s);

            a--;

            uni(a,b,s);

        }

        printf("%d\n",ans);

    }

    return ;

}