import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int HPtaka = sc.nextInt();
        int APtaka = sc.nextInt();
        int HPao = sc.nextInt();
        int APao = sc.nextInt();
        int flag = 0;
        while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int HPtaka = sc.nextInt();
        int APtaka = sc.nextInt();
        int HPao = sc.nextInt();
        int APao = sc.nextInt();
        int flag = 0;
        while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} Main public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int HPtaka = sc.nextInt();
        int APtaka = sc.nextInt();
        int HPao = sc.nextInt();
        int APao = sc.nextInt();
        int flag = 0;
        while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    } main {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int HPtaka = sc.nextInt();
        int APtaka = sc.nextInt();
        int HPao = sc.nextInt();
        int APao = sc.nextInt();
        int flag = 0;
        while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int HPtaka = sc.nextInt(); HPtaka sc.nextInt() sc.nextInt sc int APtaka = sc.nextInt(); APtaka sc.nextInt() sc.nextInt sc int HPao = sc.nextInt(); HPao sc.nextInt() sc.nextInt sc int APao = sc.nextInt(); APao sc.nextInt() sc.nextInt sc int flag = 0; flag 0 while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        } true {
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        } HPao -= APtaka HPao APtaka if(0 >= HPao){
                flag += 1;
                break;
            } 0 >= HPao 0 HPao {
                flag += 1;
                break;
            } flag += 1 flag 1 break; HPtaka -= APao HPtaka APao if(0 >= HPtaka){
                break;
            } 0 >= HPtaka 0 HPtaka {
                break;
            } break; if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        } flag == 1 flag 1 {
            System.out.println("Yes");
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
            System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int HPtaka = sc.nextInt();
        int APtaka = sc.nextInt();
        int HPao = sc.nextInt();
        int APao = sc.nextInt();
        int flag = 0;
        while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int HPtaka = sc.nextInt();
        int APtaka = sc.nextInt();
        int HPao = sc.nextInt();
        int APao = sc.nextInt();
        int flag = 0;
        while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        int HPtaka = sc.nextInt();
        int APtaka = sc.nextInt();
        int HPao = sc.nextInt();
        int APao = sc.nextInt();
        int flag = 0;
        while(true){
            HPao -= APtaka;
            if(0 >= HPao){
                flag += 1;
                break;
            }
            HPtaka -= APao;
            if(0 >= HPtaka){
                break;
            }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
}
