import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int health1 = sc.nextInt();
    int strength1 = sc.nextInt();
    int health2 = sc.nextInt();
    int strength2 = sc.nextInt();
    while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    }
    if (health1 > health2) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
} import java.util.Arrays; Arrays java.util import java.util.Collections; Collections java.util import java.util.LinkedList; LinkedList java.util import java.util.Scanner; Scanner java.util public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int health1 = sc.nextInt();
    int strength1 = sc.nextInt();
    int health2 = sc.nextInt();
    int strength2 = sc.nextInt();
    while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    }
    if (health1 > health2) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int health1 = sc.nextInt();
    int strength1 = sc.nextInt();
    int health2 = sc.nextInt();
    int strength2 = sc.nextInt();
    while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    }
    if (health1 > health2) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  } main {
    Scanner sc = new Scanner(System.in);
    int health1 = sc.nextInt();
    int strength1 = sc.nextInt();
    int health2 = sc.nextInt();
    int strength2 = sc.nextInt();
    while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    }
    if (health1 > health2) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int health1 = sc.nextInt(); health1 sc.nextInt() sc.nextInt sc int strength1 = sc.nextInt(); strength1 sc.nextInt() sc.nextInt sc int health2 = sc.nextInt(); health2 sc.nextInt() sc.nextInt sc int strength2 = sc.nextInt(); strength2 sc.nextInt() sc.nextInt sc while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    } true {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    } health2 -= strength1 health2 strength1 if ( health2 <= 0) break; health2 <= 0 health2 0 break; health1 -= strength2 health1 strength2 if (health1 <=0) break; health1 <=0 health1 0 break; if (health1 > health2) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    } health1 > health2 health1 health2 {
      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 health1 = sc.nextInt();
    int strength1 = sc.nextInt();
    int health2 = sc.nextInt();
    int strength2 = sc.nextInt();
    while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    }
    if (health1 > health2) {
      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 health1 = sc.nextInt();
    int strength1 = sc.nextInt();
    int health2 = sc.nextInt();
    int strength2 = sc.nextInt();
    while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    }
    if (health1 > health2) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
} Main
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int health1 = sc.nextInt();
    int strength1 = sc.nextInt();
    int health2 = sc.nextInt();
    int strength2 = sc.nextInt();
    while (true) {
      health2 -= strength1;
      if ( health2 <= 0) break;
      health1 -= strength2;
      if (health1 <=0) break;
    }
    if (health1 > health2) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
}