import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int flag = 0;
      
      while(a != 0 || c != 0){
        c -= b;
        if(c <= 0){
          flag = 1;
          break;
        }
        a -= d;
        if(a <= 0){
          flag = 2;
          break;
        }
      }
      if(flag == 1){
        System.out.println("Yes");
      } else if (flag == 2) {
        System.out.println("No");
      }
    }
} import java.util.*; util.* java class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int flag = 0;
      
      while(a != 0 || c != 0){
        c -= b;
        if(c <= 0){
          flag = 1;
          break;
        }
        a -= d;
        if(a <= 0){
          flag = 2;
          break;
        }
      }
      if(flag == 1){
        System.out.println("Yes");
      } else if (flag == 2) {
        System.out.println("No");
      }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int flag = 0;
      
      while(a != 0 || c != 0){
        c -= b;
        if(c <= 0){
          flag = 1;
          break;
        }
        a -= d;
        if(a <= 0){
          flag = 2;
          break;
        }
      }
      if(flag == 1){
        System.out.println("Yes");
      } else if (flag == 2) {
        System.out.println("No");
      }
    } main {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int flag = 0;
      
      while(a != 0 || c != 0){
        c -= b;
        if(c <= 0){
          flag = 1;
          break;
        }
        a -= d;
        if(a <= 0){
          flag = 2;
          break;
        }
      }
      if(flag == 1){
        System.out.println("Yes");
      } else if (flag == 2) {
        System.out.println("No");
      }
    } 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 int flag = 0; flag 0 while(a != 0 || c != 0){
        c -= b;
        if(c <= 0){
          flag = 1;
          break;
        }
        a -= d;
        if(a <= 0){
          flag = 2;
          break;
        }
      } a != 0 || c != 0 a != 0 a 0 c != 0 c 0 {
        c -= b;
        if(c <= 0){
          flag = 1;
          break;
        }
        a -= d;
        if(a <= 0){
          flag = 2;
          break;
        }
      } c -= b c b if(c <= 0){
          flag = 1;
          break;
        } c <= 0 c 0 {
          flag = 1;
          break;
        } flag = 1 flag 1 break; a -= d a d if(a <= 0){
          flag = 2;
          break;
        } a <= 0 a 0 {
          flag = 2;
          break;
        } flag = 2 flag 2 break; if(flag == 1){
        System.out.println("Yes");
      } else if (flag == 2) {
        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" if (flag == 2) {
        System.out.println("No");
      } flag == 2 flag 2 {
        System.out.println("No");
      } System.out.println("No") System.out.println System.out System System.out "No" String[] args args
import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int flag = 0;
      
      while(a != 0 || c != 0){
        c -= b;
        if(c <= 0){
          flag = 1;
          break;
        }
        a -= d;
        if(a <= 0){
          flag = 2;
          break;
        }
      }
      if(flag == 1){
        System.out.println("Yes");
      } else if (flag == 2) {
        System.out.println("No");
      }
    }
}