#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 xf = false, yf = false;
    int px, py;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0 > 0)
        {
            if(px != x)
                xf = true;
            if(py != y)
                yf = true;
        }
        px = x;
        py = y;
    }
    if(xf && yf)
        cout << "NO\n";
    else
        cout << "YES\n";
    return 0;
}