import java.util.Scanner;

public class mortgage
{
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
	
	int y, n;
	double x, r;
	
	while (true)
	{
	    x = input.nextDouble();
	    y = input.nextInt();
	    n = input.nextInt();
	    r = input.nextDouble();
	 
	    if (x == 0 && y ==0 && n == 0 && r == 0)
	    {
		break;
	    }
	    
	    int cycleCount = n * 12;
	    
	    if ((y * cycleCount) < x)
	    {
		System.out.println("NO");
		continue;
	    }
	    
	    for (int i = 1; i <= cycleCount; i++)
	    {
		x += x * (r / 1200);
		x -= y;
		
		if (x <= 0.0)
		{
		    break;
		}
	    }
	    
	    System.out.println(x <= 0.0 ? "YES" : "NO");
	}
    }
}