#include<stdio.h>
int kou(int a, int b, int c, int d){
  int t,j;
  	while(t != 0){
		t = c - b;
      	h = a - d;
    }
      if(t <= 0){
		printf("No");
      }else{
		printf("Yes");
      }
  return 0;
}
      
int main(void){
	int a,b,c,d;
  scanf("%d %d %d %d",&a,&b,&c,&d);
  kou(a,b,c,d);
  return 0;
}
  