#include<iostream>
#include<stdio.h>
#include<vector>
using namespace std;
vector<int> a[100010];
short ut[100010];
int x,y,nr;
void dfs(int nod)
{
	ut[nod]=1;
	vector<int> ::iterator it;
	for(it=a[nod].begin();it!=a[nod].end();it++)
		if(!ut[*it])
			dfs(*it);
}
int main()
{
	freopen("a.in","r",stdin);
	freopen("a.out","w",stdout);
	int i,n;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		scanf("%d",&x,&y);
		a[x].push_back(y);
		a[y].push_back(x);
	}
	for(i=1;i<=n;i++)
		if(!ut[i])
		{
			nr++;
			dfs(i);
		}
	printf("%d\n",nr);
	return 0;
}