import java.util.Scanner;


public class mortgage {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		double x;
		double y;
		double n;
		double r;
		double sum;
		
		Scanner sc = new Scanner(System.in);
	
		
		while(((x=sc.nextDouble())!=0)&&((y=sc.nextDouble())!=0)&&((n=sc.nextDouble())!=0)) {
			
			sum=x;
			
			r=sc.nextDouble();
			
			if (r == 0 && n * 12 * y >= x)
				System.out.println("YES");
			else if ((n*12*y) < x) { //splatky nestacia na pozicku bez urokov
				System.out.println("NO");
			} else if( x*(r/1200) >= y) { //vyssi urok, ako splatka
				System.out.println("NO");
			} else {
				vypocet:
				for(int i=0;i<n;i++) {
					for(int j=0;j<12;j++) {
						
						sum+=(r/1200)*sum - y;

						if(sum<=0) {
							break vypocet;
						}
						
					}
				}
				
				if(sum<=0) {
					System.out.println("YES");
				} else {
					System.out.println("NO");
				}
			}
			
			
		}
		
	}
	

}