#include <stdio.h>
#include <string.h>
#include <math.h>

int main()
{
  float pujcka, spl, rok, urok;
  float vysl;
  float celk_spl;

  int i1,i2,i3;

  while(1) {
    scanf("%d %d %d %f", &i1, &i2, &i3, &urok);
    pujcka = (float)i1;
    spl = (float)i2;
    rok = (float)i3;
    if (pujcka == 0 && spl == 0 && rok == 0 && urok == 0.f) break;

    rok *= 12.f;
    urok = (urok+1200.f)/1200.f;
    vysl = pujcka * pow(urok, rok);
    celk_spl = spl * (1 - pow(urok, rok)) / (1 - urok);
    
    if (celk_spl >= vysl) printf("YES\n");
    else printf("NO\n");

  }

  return 0;
}