/* -*- coding: utf-8 -*-
 *
 * 1829.cc:  No.1829 Möbius Tunnelling - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int n, a, b, c;
  scanf("%d%d%d%d", &n, &a, &b, &c);

  if (a < min(b, c) || a > max(b, c)) puts("Yes");
  else puts("No");
  return 0;
}