import java.util.Scanner;

public class Main {
    
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int takahashiHP = scanner.nextInt();
        int takahashiAttack = scanner.nextInt();

        int aokiHP = scanner.nextInt();
        int aokiAttack = scanner.nextInt();
        
        while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int takahashiHP = scanner.nextInt();
        int takahashiAttack = scanner.nextInt();

        int aokiHP = scanner.nextInt();
        int aokiAttack = scanner.nextInt();
        
        while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} Main public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int takahashiHP = scanner.nextInt();
        int takahashiAttack = scanner.nextInt();

        int aokiHP = scanner.nextInt();
        int aokiAttack = scanner.nextInt();
        
        while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        }
    } main {

        Scanner scanner = new Scanner(System.in);

        int takahashiHP = scanner.nextInt();
        int takahashiAttack = scanner.nextInt();

        int aokiHP = scanner.nextInt();
        int aokiAttack = scanner.nextInt();
        
        while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        }
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int takahashiHP = scanner.nextInt(); takahashiHP scanner.nextInt() scanner.nextInt scanner int takahashiAttack = scanner.nextInt(); takahashiAttack scanner.nextInt() scanner.nextInt scanner int aokiHP = scanner.nextInt(); aokiHP scanner.nextInt() scanner.nextInt scanner int aokiAttack = scanner.nextInt(); aokiAttack scanner.nextInt() scanner.nextInt scanner while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        } true {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        } aokiHP -= takahashiAttack aokiHP takahashiAttack if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            } aokiHP <= 0 aokiHP 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; takahashiHP -= aokiAttack takahashiHP aokiAttack if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            } takahashiHP <= 0 takahashiHP 0 {
                System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; String[] args args public class Main {
    
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int takahashiHP = scanner.nextInt();
        int takahashiAttack = scanner.nextInt();

        int aokiHP = scanner.nextInt();
        int aokiAttack = scanner.nextInt();
        
        while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} public class Main {
    
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int takahashiHP = scanner.nextInt();
        int takahashiAttack = scanner.nextInt();

        int aokiHP = scanner.nextInt();
        int aokiAttack = scanner.nextInt();
        
        while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} Main
import java.util.Scanner;

public class Main {
    
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int takahashiHP = scanner.nextInt();
        int takahashiAttack = scanner.nextInt();

        int aokiHP = scanner.nextInt();
        int aokiAttack = scanner.nextInt();
        
        while(true) {
            aokiHP -= takahashiAttack;
            if(aokiHP <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiHP -= aokiAttack;
            if(takahashiHP <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
}