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 x = 0;
    int y = 0;

    while(A > 0) {
      A = A - D;
      x++;
    }
    while(C > 0) {
      C = C - B;
      y++;
    }
    if (x >= y) {
      System.out.println("Yes");
    } else {
      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 x = 0;
    int y = 0;

    while(A > 0) {
      A = A - D;
      x++;
    }
    while(C > 0) {
      C = C - B;
      y++;
    }
    if (x >= y) {
      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();
    int x = 0;
    int y = 0;

    while(A > 0) {
      A = A - D;
      x++;
    }
    while(C > 0) {
      C = C - B;
      y++;
    }
    if (x >= y) {
      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();
    int x = 0;
    int y = 0;

    while(A > 0) {
      A = A - D;
      x++;
    }
    while(C > 0) {
      C = C - B;
      y++;
    }
    if (x >= y) {
      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 x = 0; x 0 int y = 0; y 0 while(A > 0) {
      A = A - D;
      x++;
    } A > 0 A 0 {
      A = A - D;
      x++;
    } A = A - D A A - D A D x++ x while(C > 0) {
      C = C - B;
      y++;
    } C > 0 C 0 {
      C = C - B;
      y++;
    } C = C - B C C - B C B y++ y if (x >= y) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    } x >= y x y {
      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
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 x = 0;
    int y = 0;

    while(A > 0) {
      A = A - D;
      x++;
    }
    while(C > 0) {
      C = C - B;
      y++;
    }
    if (x >= y) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
}