#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <queue>
#include <vector>
#include <stack>

using namespace std;

int main()
{
    int n,x = 0,y = 0,X,Y,fx = 1,fy = 1;

    scanf("%d", &n);
    scanf("%d%d", &X,&Y);
    n--;
    while( n-- ){
        scanf("%d%d", &x,&y);
        if(X != x) fx = 0;
        if(Y != y) fy = 0;
    }
    if( fx || fy )
        printf("YES\n");
    else
        printf("NO\n");
    return 0;
}