import java.util.Scanner;
public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
  int a=kbd.nextInt();
    int b=kbd.nextInt();
      int c=kbd.nextInt();
        int d=kbd.nextInt();

    while(c>0&&a>0){
    c=c-b;
    a=a-d;
  }
int n=0;
    if(c<=0){
    n=0;
  }
  if(a<=0){
    n=1;
  }
  if(c<=0&&a<=0){
    n=0;
  }
  if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
}
}
} import java.util.Scanner; Scanner java.util public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
  int a=kbd.nextInt();
    int b=kbd.nextInt();
      int c=kbd.nextInt();
        int d=kbd.nextInt();

    while(c>0&&a>0){
    c=c-b;
    a=a-d;
  }
int n=0;
    if(c<=0){
    n=0;
  }
  if(a<=0){
    n=1;
  }
  if(c<=0&&a<=0){
    n=0;
  }
  if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
}
}
} Main public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
  int a=kbd.nextInt();
    int b=kbd.nextInt();
      int c=kbd.nextInt();
        int d=kbd.nextInt();

    while(c>0&&a>0){
    c=c-b;
    a=a-d;
  }
int n=0;
    if(c<=0){
    n=0;
  }
  if(a<=0){
    n=1;
  }
  if(c<=0&&a<=0){
    n=0;
  }
  if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
}
} main {
   Scanner kbd = new Scanner(System.in);
  int a=kbd.nextInt();
    int b=kbd.nextInt();
      int c=kbd.nextInt();
        int d=kbd.nextInt();

    while(c>0&&a>0){
    c=c-b;
    a=a-d;
  }
int n=0;
    if(c<=0){
    n=0;
  }
  if(a<=0){
    n=1;
  }
  if(c<=0&&a<=0){
    n=0;
  }
  if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
}
} Scanner kbd = new Scanner(System.in); kbd new Scanner(System.in) int a=kbd.nextInt(); a kbd.nextInt() kbd.nextInt kbd int b=kbd.nextInt(); b kbd.nextInt() kbd.nextInt kbd int c=kbd.nextInt(); c kbd.nextInt() kbd.nextInt kbd int d=kbd.nextInt(); d kbd.nextInt() kbd.nextInt kbd while(c>0&&a>0){
    c=c-b;
    a=a-d;
  } c>0&&a>0 c>0 c 0 a>0 a 0 {
    c=c-b;
    a=a-d;
  } c=c-b c c-b c b a=a-d a a-d a d int n=0; n 0 if(c<=0){
    n=0;
  } c<=0 c 0 {
    n=0;
  } n=0 n 0 if(a<=0){
    n=1;
  } a<=0 a 0 {
    n=1;
  } n=1 n 1 if(c<=0&&a<=0){
    n=0;
  } c<=0&&a<=0 c<=0 c 0 a<=0 a 0 {
    n=0;
  } n=0 n 0 if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
} n==0 n 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 kbd = new Scanner(System.in);
  int a=kbd.nextInt();
    int b=kbd.nextInt();
      int c=kbd.nextInt();
        int d=kbd.nextInt();

    while(c>0&&a>0){
    c=c-b;
    a=a-d;
  }
int n=0;
    if(c<=0){
    n=0;
  }
  if(a<=0){
    n=1;
  }
  if(c<=0&&a<=0){
    n=0;
  }
  if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
}
}
} public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
  int a=kbd.nextInt();
    int b=kbd.nextInt();
      int c=kbd.nextInt();
        int d=kbd.nextInt();

    while(c>0&&a>0){
    c=c-b;
    a=a-d;
  }
int n=0;
    if(c<=0){
    n=0;
  }
  if(a<=0){
    n=1;
  }
  if(c<=0&&a<=0){
    n=0;
  }
  if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
}
}
} Main
import java.util.Scanner;
public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
  int a=kbd.nextInt();
    int b=kbd.nextInt();
      int c=kbd.nextInt();
        int d=kbd.nextInt();

    while(c>0&&a>0){
    c=c-b;
    a=a-d;
  }
int n=0;
    if(c<=0){
    n=0;
  }
  if(a<=0){
    n=1;
  }
  if(c<=0&&a<=0){
    n=0;
  }
  if(n==0){
    System.out.println("Yes");
}else{
    System.out.println("No");
}
}
}