#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n,x[13],y[13],f=0;
    bool b=true;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        cin >> x[a0] >> y[a0];
    }
    if(x[0]==x[1]&&y[0]!=y[1])
        f = 1;
    if(y[0]==y[1]&&x[0]!=x[1])
        f = 2;
    if(x[0]!=x[1]&&y[0]!=y[1])
        b = false;
    for(int i=2;i<n;i++){
        if(f==0){
            if(x[i]==x[0]&&y[i]!=y[0])
                f = 1;
            if(x[i]!=x[0]&&y[i]==y[0])
                f = 2;
            if(x[i]!=x[0]&&y[i]!=y[0]){
                b = false;
                break;
            }
            
        }
        else if(f==1){
            if(x[i]!=x[0]){
                b = false;
                break;
            }
        }
        else{
            if(y[i]!=y[0]){
                b = false;
                break;
            }
        }
    }
    if(b)
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
    return 0;
}