#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n, x, y, a, b, f1 = 0, f2 = 0;
    cin >> n;
    cin>>x>>y;
    for(int i = 1; i < n; i++){
        cin>>a>>b;
        if(a!=x)
            f1=1;
        if(b!=y)
            f2=1;
    }

    if(f1 == 0 || f2 == 0){
        cout<<"YES";
    }
    else{
        cout<<"NO";
    }
    
    return 0;
}