#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");
const int N = 100001;

int n,m;
bool viz[N];
vector<int> a[N];

void dfs(int x){
    viz[x]=1;
    int i;
    for(i=0;i<a[x].size();i++)
        if(!viz[a[x][i]])
            dfs(a[x][i]);
}

int main()
{
    fin>>n>>m;
    int i,j,k;
    for(k=1;k<=n;k++){
        fin>>i>>j;
        a[i].push_back(j);
        a[j].push_back(i);
    }
    k=0;
    for(i=1;i<=n;i++)
        if(!viz[i]){
            k++;
            dfs(i);
        }
    fout<<k;
    return 0;
}