#include <iostream>
#include <fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
const int N=100001,M=200001;
int lst[N],vf[2*M],urm[2*M],nr,viz[N],comp,n,m;
void adauga(int x,int y){
    vf[++nr]=y;
    urm[nr]=lst[x];
    lst[x]=nr;
}
void dfs(int x){
   viz[x]=comp;
   int p=lst[x],y;
   while(p!=0){
       y=vf[p];
       if(!viz[y])
          dfs(y);
        p=urm[p];
   }
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++){
        int x,y;
        f>>x>>y;
        adauga(x,y);
        adauga(y,x);
    }
    for(int i=1;i<=n;i++)
        if(!viz[i]){
            comp++;
            dfs(i);
        }
    g<<comp;
    return 0;
}