import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner scan = new Scanner(System.in);
        int A1=scan.nextInt();
        int A2=scan.nextInt();
        int B1=scan.nextInt();
        int B2=scan.nextInt();
        while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        }
        
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner scan = new Scanner(System.in);
        int A1=scan.nextInt();
        int A2=scan.nextInt();
        int B1=scan.nextInt();
        int B2=scan.nextInt();
        while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        }
        
    }
} Main public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner scan = new Scanner(System.in);
        int A1=scan.nextInt();
        int A2=scan.nextInt();
        int B1=scan.nextInt();
        int B2=scan.nextInt();
        while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        }
        
    } main {
        // Your code here!
        Scanner scan = new Scanner(System.in);
        int A1=scan.nextInt();
        int A2=scan.nextInt();
        int B1=scan.nextInt();
        int B2=scan.nextInt();
        while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        }
        
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int A1=scan.nextInt(); A1 scan.nextInt() scan.nextInt scan int A2=scan.nextInt(); A2 scan.nextInt() scan.nextInt scan int B1=scan.nextInt(); B1 scan.nextInt() scan.nextInt scan int B2=scan.nextInt(); B2 scan.nextInt() scan.nextInt scan while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        } true {
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        } B1=B1-A2 B1 B1-A2 B1 A2 if(B1<=0){
                System.out.println("Yes");
                break;
            } B1<=0 B1 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; A1=A1-B2 A1 A1-B2 A1 B2 if(A1<=0){
                System.out.println("No");
                break;
            } A1<=0 A1 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) throws Exception {
        // Your code here!
        Scanner scan = new Scanner(System.in);
        int A1=scan.nextInt();
        int A2=scan.nextInt();
        int B1=scan.nextInt();
        int B2=scan.nextInt();
        while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        }
        
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner scan = new Scanner(System.in);
        int A1=scan.nextInt();
        int A2=scan.nextInt();
        int B1=scan.nextInt();
        int B2=scan.nextInt();
        while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        }
        
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner scan = new Scanner(System.in);
        int A1=scan.nextInt();
        int A2=scan.nextInt();
        int B1=scan.nextInt();
        int B2=scan.nextInt();
        while(true){
            B1=B1-A2;
            if(B1<=0){
                System.out.println("Yes");
                break;
            }
            A1=A1-B2;
            if(A1<=0){
                System.out.println("No");
                break;
            }
        }
        
    }
}
