#include<bits/stdc++.h>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int n,x[21],y[21],a,b,flag=false,i;
    memset(x,0,sizeof(x));
    memset(y,0,sizeof(y));
    cin>>n;
    for(i=0;i<n;i++){
        cin>>a>>b;
        x[a+10]++;
        y[b+10]++;
    }
    for( i=0;i<=20;i++){
        if(x[i] == n || y[i] == n){
            flag=true;
            break;
        }   
    }
    if(flag)
        cout<<"YES\n";
    else
        cout<<"NO\n";
    return 0;
}