#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;
    cin >> n;
    int a,b,f1=1,f2=1;
    for(int i = 0; i < n; i++){
        int x;
        int y;
        cin >> x >> y;
        
        if(!i)
        {
            a=x;
            b=y;
        }
        
        if(x!=a)f1=0;
        if(y!=b)f2=0;
    }
    
    if(f1 || f2)cout<<"YES";else cout<<"NO";
    return 0;
}