import java.util.Scanner;

/*
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 * and open the template in the editor.
 */

/**
 *
 * @author cteam043
 */
public class mortgage {
    
    public static void main(String[] args) {
        
        long y, n;
        double r, x;
        boolean t = false;
        
        Scanner sc = new Scanner(System.in);
        
        while (true) {
            
            x = sc.nextInt();
            y = sc.nextInt();
            n = sc.nextInt()*12;
            r = sc.nextDouble();
            
            if (x+y+n+r == 0) {
                break;
            }
            
            r /= 1200;
            for (int i = 0; i < n; i++) {
                
                x = x*(1+r);
                if (x < y) {
                    System.out.println("YES");
                    t = true;
                    break;
                }
                
                x = x - y;

            }
            
            
            if (t) {
                t = false;
            } else {
                 System.out.println("NO");    
            }
                
           
            
        }
        
    }


}