#include<stdio.h>
int maiin()

{
	long long int A,B,C,D;

	scanf("%lld%lld%lld%lld",&A,&B,&C,&D);

	while(A>=0 && C>=0)
{

        C = C - B;
	if(C<=0){
	    printf("Yes\n");
	   break;}

       A=A-D;	
	if(A<=0){
	    printf("No\n");
	    break;
	}
	     }
	      return 0;
}
