#include <stdio.h>

int main()
{
	int N, a, b, c;
	scanf("%d", &N);
	scanf("%d %d %d", &a, &b, &c);
	if (c == a || (c < a && a < b) || (b < a && a < c)) printf("No\n");
	else printf("Yes\n");
	fflush(stdout);
	return 0;
}