#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int x[11],y[11];

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int n;
    cin>>n;
    int f1=0,f2=0;
    for(int i=0;i<n;i++)
        {
        cin>>x[i]>>y[i];
    }
    for(int i=0;i<n-1;i++)
        {
        if(x[i]==x[i+1])
            {
            f1++;
        }
    }
    for(int i=0;i<n-1;i++)
        {
        if(y[i]==y[i+1])
            {
            f2++;
            //break;
        }
    }
    if(f1==(n-1) || f2==(n-1))
        cout<<"YES\n";
    else
        cout<<"NO\n";
    
    return 0;
}