#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 */   
    int n;
    scanf("%d", &n);
    
    int a[n], b[n];
    for(int i=0; i<n; i++) scanf("%d %d", a+i, b+i);
    
    int x = 1, y = 1;
    for(int i=1; i<n; i++){
        if(a[i] != a[0]) x = 0;
        if(b[i] != b[0]) y = 0;
    }
    
    if(x || y) puts("YES");
    else puts("NO");
    return 0;
}