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

const int N = 100001;
const char inf[] = "dfs.in";
const char outf[] = "dfs.out";

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

ifstream fin(inf);
ofstream fout(outf);

void cit(){
    fin>>n;
    int i,x,y;
    for(i=1;i<=n;i++){
        fin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}

void DFS(int x){
    viz[x]=1;
    for(auto it : a[x]){
        if(viz[it]==0)
            DFS(it);
    }
}

int main()
{
    cit();
    int i,cc=0;
    for(i=1;i<=n;i++)
        if(viz[i]==0){
            DFS(i);
            cc++;
        }
    fout<<cc;
    return 0;
}