#include <cstdio>

int main()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);

    int i,n,m,v[100001],x,y,aux,nr=0;

    scanf("%d %d", &n, &m);

    for(i=1; i<=n; i++)   v[i]=i;
    for(i=1;i<=m;i++)
    {scanf("%d %d", &x, &y);
     while(x!=v[x]) aux=v[v[x]],v[x]=aux,x=aux;
     while(y!=v[y]) aux=v[v[y]],v[y]=aux,y=aux;
     if(x!=y){
            nr++; v[x]=y;
        }
    }
    printf("%d\n" ,n-nr);
}