import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        }
    }
} import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        }
    }
} Main public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        }
    } main {
        Scanner scanner = new Scanner(System.in);
        
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        }
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int a = scanner.nextInt(); a scanner.nextInt() scanner.nextInt scanner int b = scanner.nextInt(); b scanner.nextInt() scanner.nextInt scanner int c = scanner.nextInt(); c scanner.nextInt() scanner.nextInt scanner int d = scanner.nextInt(); d scanner.nextInt() scanner.nextInt scanner for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        } ; {
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        } {
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        } c = c - b c c - b c b if(c <= 0){
                System.out.println("Yes");
                break;
            } c <= 0 c 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; a = a - d a a - d a d if(a <= 0){
                System.out.println("No");
                break;
            } a <= 0 a 0 {
                System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; String[] args args public class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        }
    }
} public class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        }
    }
} Main
import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        for(;;){
            c = c - b;
            if(c <= 0){
                System.out.println("Yes");
                break;
            }
            a = a - d;
            if(a <= 0){
                System.out.println("No");
                break;
            }
        }
    }
}