#include <fstream>
#include <vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
vector<int> a[100001];
int viz[100001],n,m,nr;
void cit(){
    f>>n>>m;
    int x,y;
    for(int i=1;i<=n;i++){
        f>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);}
}
void dfs(int x){
    viz[x]=1;
    for(int i=0;i<a[x].size();++i)
        if(!viz[a[x][i]])
            dfs(a[x][i]);
}
int main()
{
    cit();
    for(int i=1;i<=n;i++)
        if(!viz[i])
            dfs(i),++nr;
    g<<nr;
    return 0;
}