#include<stdio.h>
int v[100005], w[100005];
int main()
{
	int n;
	scanf("%d", &n);
	int i;
	for (i = 0; i < n; i++)
		scanf("%d %d", &v[i], &w[i]);
	int f = 0;
	for (i = 0; i < n; i++)
		if (w[i] == 1)
			f++;
	if (f > 0)
		printf("Yes\n");
	else
		printf("No\n");
	return 0;
}