import java.util.*;
public class Main {
	public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      //取得
      int A = sc.nextInt();
      int B = sc.nextInt();
      int C = sc.nextInt();
      int D = sc.nextInt();
      int i = 1;
      //どちらかが体力なくなるまで対戦
      //奇数回は高橋の攻撃
      while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      }
      //高モンの体力は？
      if(A>0){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      }
    }
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      //取得
      int A = sc.nextInt();
      int B = sc.nextInt();
      int C = sc.nextInt();
      int D = sc.nextInt();
      int i = 1;
      //どちらかが体力なくなるまで対戦
      //奇数回は高橋の攻撃
      while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      }
      //高モンの体力は？
      if(A>0){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      }
    }
} Main public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      //取得
      int A = sc.nextInt();
      int B = sc.nextInt();
      int C = sc.nextInt();
      int D = sc.nextInt();
      int i = 1;
      //どちらかが体力なくなるまで対戦
      //奇数回は高橋の攻撃
      while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      }
      //高モンの体力は？
      if(A>0){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      }
    } main {
      Scanner sc = new Scanner(System.in);
      //取得
      int A = sc.nextInt();
      int B = sc.nextInt();
      int C = sc.nextInt();
      int D = sc.nextInt();
      int i = 1;
      //どちらかが体力なくなるまで対戦
      //奇数回は高橋の攻撃
      while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      }
      //高モンの体力は？
      if(A>0){
        System.out.println("Yes");
      }else{
        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 i = 1; i 1 while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      } A>0 && C>0 A>0 A 0 C>0 C 0 {
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      } if(i%2==1){
          C-=B;
        }else{
          A-=D;
        } i%2==1 i%2 i 2 1 {
          C-=B;
        } C-=B C B {
          A-=D;
        } A-=D A D i++ i if(A>0){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      } A>0 A 0 {
        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){
      Scanner sc = new Scanner(System.in);
      //取得
      int A = sc.nextInt();
      int B = sc.nextInt();
      int C = sc.nextInt();
      int D = sc.nextInt();
      int i = 1;
      //どちらかが体力なくなるまで対戦
      //奇数回は高橋の攻撃
      while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      }
      //高モンの体力は？
      if(A>0){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      }
    }
} public class Main {
	public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      //取得
      int A = sc.nextInt();
      int B = sc.nextInt();
      int C = sc.nextInt();
      int D = sc.nextInt();
      int i = 1;
      //どちらかが体力なくなるまで対戦
      //奇数回は高橋の攻撃
      while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      }
      //高モンの体力は？
      if(A>0){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      }
    }
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      //取得
      int A = sc.nextInt();
      int B = sc.nextInt();
      int C = sc.nextInt();
      int D = sc.nextInt();
      int i = 1;
      //どちらかが体力なくなるまで対戦
      //奇数回は高橋の攻撃
      while(A>0 && C>0){
        if(i%2==1){
          C-=B;
        }else{
          A-=D;
        }
        i++;
      }
      //高モンの体力は？
      if(A>0){
        System.out.println("Yes");
      }else{
        System.out.println("No");
      }
    }
}