#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    ios::sync_with_stdio(false);
    int n,x,y,x1,y1;
    cin>>n;
    cin>>x>>y;
    n--;
    int flag = 1;
    while(n--){
        cin>>x1>>y1;
        if(x != x1 && y != y1){
            cout<<"NO"<<endl;
            flag = 0;
            break;
        }
    }    
    if(flag){
        cout<<"YES"<<endl;
    }
    return 0;
}