#include <fstream>
#include <vector>
using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");

vector<int> liste[100001];
int viz[100001];

void DFS(int x){
    viz[x]=true;
    for (vector<int>::iterator i=liste[x].begin();i!=liste[x].end();i++){
        if (!viz[*i]){
            DFS(*i);
        }
    }
}

int main(){
    int n,m;
    in>>n>>m;
    int x1,x2;
    for (int i=1;i<=n;i++){
        in>>x1>>x2;
        liste[x1].push_back(x2);
        liste[x2].push_back(x1);
    }
    int count=0;
    for (int i=1;i<=n;i++)
        if (!viz[i]){
            DFS(i);
            count++;
    }
    out<<count;
    return 0;
}