#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 n;
int X[11];
int Y[11];

int main(){
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> X[i] >> Y[i];
    }
    
    bool horiz = true, vert = true;
    for (int i = 2; i <= n; i++) {
        if (X[i] != X[i-1])
            horiz = false;
        if (Y[i] != Y[i-1])
            vert = false;
    }
    
    if (horiz || vert)
        cout << "YES\n";
    else
        cout << "NO\n";
    
    return 0;
}