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

using namespace std;

const int N = 100001;
vector <int> a[N];
int n,m;
ifstream in("dfs.in");
ofstream out("dfs.out");

void citire(){
    in>>n>>m;
    int x,y;
    for(int i=0; i<n;i++){
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    in.close();
}

bool viz[N];

void dfs(int x){
    viz[x] = true;
    for(auto y : a[x]){
        if(!viz[y]){
            dfs(y);
        }
    }
}

int main()
{
    citire();
    int nrc = 0;
    for(int i = 1; i<=n; i++){
        if(!viz[i]){nrc++; dfs(i);}
    }
    out<<nrc;
}