#include <cstdlib>
#include <cstdio>
#include <cmath>
int main(){
int pocetMes,  pocetLet;
double pujcka,pujckaPuvodni,splatka;
float  urokZaRok, urokZaMesic;
while(1){
	scanf("%lf %lf %d %f", &pujcka, &splatka, &pocetLet, &urokZaRok);
	if( pujcka==0 && splatka==0 && pocetLet==0 && urokZaRok==0)
		return 0;
	pujckaPuvodni = pujcka;
	urokZaMesic = 1 + (urokZaRok / 1200);
        pocetMes = 12 * pocetLet;
	pujcka = (pujcka*urokZaMesic) - splatka;		
	if(pujckaPuvodni<pujcka){
		printf("NO\n");
	}

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

return 0;
}