#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
	int n;
	scanf("%d",&n);
	int i,j;
	int x,y;
	int cnt=0;
	int tmp = 0;
	int a_x[n],a_y[n];
	for(i=0;i<n;i++)
	{
		scanf("%d %d",&x,&y);
		a_x[i] = x;
		a_y[i] = y;
	}
	for(j=0;j<n;j++)
	{
		if(a_x[j] == a_x[j+1])
			cnt++;
		if(a_y[j] == a_y[j+1])
			tmp++;
	}
	if(cnt == n-1 || tmp == n-1)
	{
		printf("YES");
	}
	else
	{
		printf("NO");
	}
	return 0;

}