#include <cstdlib>
#include <cstdio>
#include <cmath>
int main(){
int pocetMes,  pocetLet;
int pujcka,pujckaPuvodni,splatka;
double  urokZaRok, urokZaMesic;
while(1){
	scanf("%d %d %d %lf", &pujcka, &splatka, &pocetLet, &urokZaRok);
	if( pujcka==0 && splatka==0 && pocetLet==0 && urokZaRok==0)
		return 0;
	pujckaPuvodni = pujcka;
	urokZaMesic = 1 + (urokZaRok / 1200);
        pocetMes = 12 * pocetLet;


 //	for(int mesic =2; mesic <= pocetMes && pujcka>0; mesic++ ){
		//	pujcka = (pujcka*urokZaMesic) - splatka;
			//printf("%f\n",pujcka);
		//}
	double ur = 12 * (double)pocetLet / pow(urokZaMesic,pocetMes) ;
//printf("%f\n",ur);
	ur = (double)pujckaPuvodni - ur * (double) splatka;
//printf("%f\n",ur);
		if(ur>0)
			printf("NO\n");
		else
			printf("YES\n");
	
}

return 0;
}