#include <cstdio>

int i,n,m,v[100001],x,y,nr=0;
FILE*f=freopen("dfs.in","r",stdin);
FILE*g=freopen("dfs.out","w",stdout);

int main()
{
    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]) x=v[x];
     while(y!=v[y]) y=v[y];
     if(x!=y){
            nr++; v[x]=y;
        }
    }
    printf("%d\n" ,n-nr);
}