#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,check=1;
    cin >> n;
    float x[n];
    float y[n];
    for(int a0 = 0; a0 < n; a0++){
        cin >> x[a0] >> y[a0];
    }
    if(x[1]==x[0])
        {
        for(int a0 = 2; a0 < n; a0++){
        if(x[a0]!=x[0]){check=0;}
        }}
    else if(y[1]==y[0])
    {
         for(int a0 = 2; a0 < n; a0++){
        if(y[a0]!=y[0]){check=0;}
        }
    }
    else {check=0;}
    if(check==1){cout<<"YES";}
    else{cout<<"NO";}
    return 0;
}