#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct check
            {
                int x,y;
            };

int main() 
{
    int n,i,f=0,g=0;
    cin >> n;
    check arr[n];
    for(i=0;i<n;i++)
        cin >> arr[i].x >> arr[i].y;
    for(i=0;i<n-1;i++)
        if(arr[i].x != arr[i+1].x)
            break;
        if(i==n-1)
            f=1;
           for(i=0;i<n-1;i++)
                if(arr[i].y != arr[i+1].y)
                    break;
            if(i==n-1)
                g=1;
    if(f==1 || g==1)
        cout << "YES\n";
    else
        cout << "NO\n";
    return 0;
}