#include<bits/stdc++.h>
#define ll long long
#define ld long double
using namespace std;
const int mod = 999983;
pair<int, int> a[15];
int main()
{
    int n;
    cin >> n;
    for(int i = 0; i < n; ++i){
        cin >> a[i].first >> a[i].second;
    }
    int allf = 1;
    int alls = 1;
    for(int i = 1; i < n; ++i){
        if (a[i].first != a[i - 1].first) allf = 0;
        if (a[i].second != a[i - 1].second) alls = 0;
    }
    cout << (allf || alls? "YES": "NO") << '\n';
}