#include <cstdio>

int i,n,m,v[100001],x,y,aux,sz[100001],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,sz[i]=1;
    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++;
            if(sz[x]<sz[y]) v[x]=y,sz[y]+=sz[x];
            else v[y]=x,sz[x]+=sz[y];
        }
    }
    printf("%d\n" ,n-nr);
}