#include <bits/stdc++.h>
using namespace std;

#define fs first
#define se second
#define pb push_back
#define mp make_pair
#define pii pair < int , int >
#define pi 2*acos(0.0)

typedef long long ll;
typedef unsigned long long llu;
typedef pair < ll , ll > pll;

const int N = 100005;

int a[15] , b[15];

int main(){
    int n; cin >> n;
    for(int i = 1;i <= n; i++) cin >> a[i] >> b[i];

    int c = 1 , d = 1;
    for(int i = 2;i <= n; i++) if(a[i] != a[i - 1]) c = 0;
    for(int i = 2;i <= n; i++) if(b[i] != b[i - 1]) d = 0;

    puts(c || d ? "YES" : "NO");

    return 0;
}