import java.util.*;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int tkMonsterHp = sc.nextInt();
    int tkMonsterAttack = sc.nextInt();
    int aoMonsterHp = sc.nextInt();
    int aoMonsterAttack = sc.nextInt();

    while (tkMonsterHp > 0 && aoMonsterHp > 0) {
      aoMonsterHp -= tkMonsterAttack;
      if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      }

      tkMonsterHp -= aoMonsterAttack;

      if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      }
      
    }
    sc.close();
  }
} import java.util.*; util.* java class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int tkMonsterHp = sc.nextInt();
    int tkMonsterAttack = sc.nextInt();
    int aoMonsterHp = sc.nextInt();
    int aoMonsterAttack = sc.nextInt();

    while (tkMonsterHp > 0 && aoMonsterHp > 0) {
      aoMonsterHp -= tkMonsterAttack;
      if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      }

      tkMonsterHp -= aoMonsterAttack;

      if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      }
      
    }
    sc.close();
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int tkMonsterHp = sc.nextInt();
    int tkMonsterAttack = sc.nextInt();
    int aoMonsterHp = sc.nextInt();
    int aoMonsterAttack = sc.nextInt();

    while (tkMonsterHp > 0 && aoMonsterHp > 0) {
      aoMonsterHp -= tkMonsterAttack;
      if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      }

      tkMonsterHp -= aoMonsterAttack;

      if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      }
      
    }
    sc.close();
  } main {
    Scanner sc = new Scanner(System.in);
    int tkMonsterHp = sc.nextInt();
    int tkMonsterAttack = sc.nextInt();
    int aoMonsterHp = sc.nextInt();
    int aoMonsterAttack = sc.nextInt();

    while (tkMonsterHp > 0 && aoMonsterHp > 0) {
      aoMonsterHp -= tkMonsterAttack;
      if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      }

      tkMonsterHp -= aoMonsterAttack;

      if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      }
      
    }
    sc.close();
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int tkMonsterHp = sc.nextInt(); tkMonsterHp sc.nextInt() sc.nextInt sc int tkMonsterAttack = sc.nextInt(); tkMonsterAttack sc.nextInt() sc.nextInt sc int aoMonsterHp = sc.nextInt(); aoMonsterHp sc.nextInt() sc.nextInt sc int aoMonsterAttack = sc.nextInt(); aoMonsterAttack sc.nextInt() sc.nextInt sc while (tkMonsterHp > 0 && aoMonsterHp > 0) {
      aoMonsterHp -= tkMonsterAttack;
      if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      }

      tkMonsterHp -= aoMonsterAttack;

      if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      }
      
    } tkMonsterHp > 0 && aoMonsterHp > 0 tkMonsterHp > 0 tkMonsterHp 0 aoMonsterHp > 0 aoMonsterHp 0 {
      aoMonsterHp -= tkMonsterAttack;
      if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      }

      tkMonsterHp -= aoMonsterAttack;

      if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      }
      
    } aoMonsterHp -= tkMonsterAttack aoMonsterHp tkMonsterAttack if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      } aoMonsterHp <= 0 aoMonsterHp 0 {
        System.out.println("Yes");
        break;
      } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; tkMonsterHp -= aoMonsterAttack tkMonsterHp aoMonsterAttack if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      } tkMonsterHp <= 0 tkMonsterHp 0 {
        System.out.println("No");
        break;
      } System.out.println("No") System.out.println System.out System System.out "No" break; sc.close() sc.close sc String[] args args
import java.util.*;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int tkMonsterHp = sc.nextInt();
    int tkMonsterAttack = sc.nextInt();
    int aoMonsterHp = sc.nextInt();
    int aoMonsterAttack = sc.nextInt();

    while (tkMonsterHp > 0 && aoMonsterHp > 0) {
      aoMonsterHp -= tkMonsterAttack;
      if(aoMonsterHp <= 0) {
        System.out.println("Yes");
        break;
      }

      tkMonsterHp -= aoMonsterAttack;

      if(tkMonsterHp <= 0) {
        System.out.println("No");
        break;
      }
      
    }
    sc.close();
  }
}