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

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

const int NMAX = 100005;
vector <int> v[NMAX];
int n,comp,viz[NMAX];

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

int main(){
    int i,x,y,j;
    f >> n;
    for(i = 1 ; i <= n ; i++){
        f >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    for(i = 1 ; i <= n ; i++)
        if(!viz[i]){
            dfs(i);
            comp++;
        }

    g << comp;

return 0;
}