//Given  two - dimensional points in space, determine whether they lie on some vertical or horizontal line.If yes, print YES; otherwise, print NO.
//
//Input Format
//
//The first line contains a single positive integer, , denoting the number of points.
//Each line  of  subsequent lines contain two space - separated integers detailing the respective values of and (i.e., the coordinates of the  point).
//
//Constraints
//
//Output Format
//
//Print YES if all points lie on some horizontal or vertical line; otherwise, print NO.
//
//Sample Input 0
//
//5
//0 1
//0 2
//0 3
//0 4
//0 5
//Sample Output 0
//
//YES
//Explanation 0
//
//All points lie on a vertical line.
//
//Sample Input 1
//
//5
//0 1
//0 2
//1 3
//0 4
//0 5
//Sample Output 1
//
//NO
//Explanation 1
//
//The points do not all form a horizontal or vertical line.

#include <cstdio>

int main() {
	int n;
	scanf("%d", &n);
	int firstX, firstY;
	scanf("%d %d", &firstX, &firstY);
	bool allHorizontal = true;
	bool allVertical = true;
	for (int i = 1; i < n; ++i) {
		int x, y;
		scanf("%d %d", &x, &y);
		allHorizontal &= x == firstX;
		allVertical &= y == firstY;
	}
	puts(allHorizontal || allVertical ? "YES" : "NO");
	return 0;
}