#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 isHorizontal = true, isVertical = true;
    int x1, x2, y1, y2;
    for(int a0 = 0; a0 < n; a0++){
        cin >> x2 >> y2;
        if(a0 == 0){
            x1 = x2;
            y1 = y2;
        }
        if(isHorizontal){
            if(y1 != y2){
                isHorizontal = false;
            }
        }
        if(isVertical){
            if(x1 != x2){
                isVertical = false;
            }
        }
        x1 = x2;
        y1 = y2;
    }
    if(isHorizontal || isVertical){
        cout << "YES" << endl;   
    }
    else{
        cout << "NO" << endl;
    }
    return 0;
}