import java.util.*;

public 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();

    boolean takahashi = true;

    while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    }

    if (c <= 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);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();

    boolean takahashi = true;

    while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    }

    if (c <= 0) {
      System.out.println("Yes");
    } else {
      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();

    boolean takahashi = true;

    while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    }

    if (c <= 0) {
      System.out.println("Yes");
    } else {
      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();

    boolean takahashi = true;

    while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    }

    if (c <= 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 boolean takahashi = true; takahashi true while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    } a > 0 && c > 0 a > 0 a 0 c > 0 c 0 {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    } if (takahashi) {
        c -= b;
      } else {
        a -= d;
      } takahashi {
        c -= b;
      } c -= b c b {
        a -= d;
      } a -= d a d takahashi = !takahashi takahashi !takahashi takahashi if (c <= 0) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    } c <= 0 c 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);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();

    boolean takahashi = true;

    while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    }

    if (c <= 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);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();

    boolean takahashi = true;

    while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    }

    if (c <= 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);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();

    boolean takahashi = true;

    while (a > 0 && c > 0) {
      if (takahashi) {
        c -= b;
      } else {
        a -= d;
      }
      takahashi = !takahashi;
    }

    if (c <= 0) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  } 
}
