//
// File:   newmain.cc
// Author: cteam057
//
// Created on October 22, 2011, 4:12 PM
//

#include <stdlib.h>
#include<stdio.h>
//
//
//
int main(int argc, char** argv) {
    
    double pujcka, splatka, roky;
    double urok;
    
    double dluh;
    float epsilon=0.0000001;
    while(true) {
        scanf("%lf %lf %lf %lf", &pujcka, &splatka, &roky, &urok );
        if(pujcka==0 && splatka==0
                && roky==0 && urok==0 ) break;
        roky=roky*12;
        dluh=pujcka;
        urok=urok/1200.0;
       // printf("%f  %f %f %f \n",pujcka, dluh,   splatka, urok);
        for(int i=1;i<=roky;i++){              //1234567890123456789012345
            if(dluh<=(0+epsilon) || dluh >=100000000000000000000000000.0){
                break;
            }
            dluh+=urok*dluh;
            dluh-=splatka;
            
        }
        
        if(dluh<=(0+epsilon)){
            printf("YES\n");
        }else{
            printf("NO\n");
        }
        
        
        
    }
    return (EXIT_SUCCESS);
}