#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>
using namespace std;

map<int,int> x,y;
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    	int n,i,j,k,l,m;
	cin>>n;
	m=n;
	int count1,count2;
	count1=count2=0;
	while (n--)
	{
		cin>>j>>k;
		if (x.find(j)!=x.end())
		count1++;
		if (y.find(k)!=y.end())
		count2++;
		x[j]++;
		y[k]++;
	}
	n=m;
	if (count1==n-1 || count2==n-1)
	cout<<"YES"<<endl;
	else
	cout<<"NO"<<endl;
	return 0;
    return 0;
}