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

set < int > x, y;
int n;

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    cin >> n;
    for(int i = 1; i <= n; ++i) {
        int X, Y; cin >> X >> Y;
        x.insert(X); y.insert(Y);
    }
    if(x.size() == 1 || y.size() == 1) puts("YES");
    else puts("NO");
    return 0;
}