#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;
	int firstx, firsty;
	string isSameX = "YES";
	string isSameY = "YES";
	cin >> n;
	if (n >= 2 && n <= 10) {
		for (int a0 = 0; a0 < n; a0++) {
			int x;
			int y;
			cin >> x >> y;
			if (x >= -10 && x <= 10 && y >= -10 && y <= 10) {
				if (a0 == 0) {
					firstx = x;
					firsty = y;
				}
				if (x != firstx) {
					isSameX = "NO";
				}
				if (y != firsty) {
					isSameY = "NO";
				}
			}

		}

		if (isSameX == "YES") {
			cout << isSameX;
		}
		else if (isSameY == "YES") {
			cout << isSameY;
		}
		else {
			cout << "NO";
		}
	}
	
    return 0;
}