import java.util.Scanner;
public class Main {
    public static void main(String[] args) throws Exception {
       Scanner sc = new Scanner(System.in);
 
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) throws Exception {
       Scanner sc = new Scanner(System.in);
 
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        }
    }
} Main public static void main(String[] args) throws Exception {
       Scanner sc = new Scanner(System.in);
 
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        }
    } main {
       Scanner sc = new Scanner(System.in);
 
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int A = sc.nextInt(); A sc.nextInt() sc.nextInt sc int B = sc.nextInt(); B sc.nextInt() sc.nextInt sc int C = sc.nextInt(); C sc.nextInt() sc.nextInt sc int D = sc.nextInt(); D sc.nextInt() sc.nextInt sc for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        } ; {
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        } {
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        } if(C <= B){
                System.out.println("Yes");
                break;
            } C <= B C B {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; C = C - B C C - B C B if(A <= D){
                 System.out.println("No");
                break;
            } A <= D A D {
                 System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; A = A - D A A - D A D String[] args args public class Main {
    public static void main(String[] args) throws Exception {
       Scanner sc = new Scanner(System.in);
 
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        }
    }
} public class Main {
    public static void main(String[] args) throws Exception {
       Scanner sc = new Scanner(System.in);
 
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        }
    }
} Main
import java.util.Scanner;
public class Main {
    public static void main(String[] args) throws Exception {
       Scanner sc = new Scanner(System.in);
 
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        for(;;){
            if(C <= B){
                System.out.println("Yes");
                break;
            }
            C = C - B;
          
            if(A <= D){
                 System.out.println("No");
                break;
            }
            A = A - D;
        }
    }
}