#include<bits/stdc++.h>
using namespace std;
int main()

{
    int n,x,y;
    cin>>n;
    int a,b;
    cin>>a>>b;
    bool aok=1,bok=1;
    for(int i=1; i<n; i++)
    {
        cin>>x>>y;
        if(aok||bok)
        {
            if(x!=a)aok=0;
            if(y!=b)bok=0;
        }
    }
    if(aok||bok)cout<<"YES"<<endl;
    else cout<<"NO"<<endl;
}