#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;
    bool x_found = true;
    bool y_found = true;
    for(int a0 = 0; a0 < n; a0++){
        int x[n];
        int y[n];
        cin >> x[a0] >> y[a0];
        if(a0 > 0 && (x[a0] != x[a0 - 1])){
            x_found = false;
        }
        
        if(a0 > 0 && y[a0] != y[a0 - 1]){
            y_found = false;
        }
    }
    if(x_found || y_found){
        cout << "YES" << endl;
    }
    else{
        cout << "NO" << endl;
    }
    
    return 0;
}