#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, y, prevX, prevY;
    bool retV = true, retH = true;
    cin >> n;
    cin >> prevX >> prevY;
    for(int a0 = 1; a0 < n; a0++){
        cin >> x >> y;
        
        if(prevX != x)
            retV = false;
        if(prevY != y)
            retH = false;
        
        if(retV == false && retH == false)
            break;
    }
    
    if(retV == false && retH == false)
        cout << "NO";
    else
        cout << "YES";
    return 0;
}