import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tt = sc.nextInt();
        int tk = sc.nextInt();
        int at = sc.nextInt();
        int ak = sc.nextInt();
        while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tt = sc.nextInt();
        int tk = sc.nextInt();
        int at = sc.nextInt();
        int ak = sc.nextInt();
        while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tt = sc.nextInt();
        int tk = sc.nextInt();
        int at = sc.nextInt();
        int ak = sc.nextInt();
        while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int tt = sc.nextInt();
        int tk = sc.nextInt();
        int at = sc.nextInt();
        int ak = sc.nextInt();
        while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int tt = sc.nextInt(); tt sc.nextInt() sc.nextInt sc int tk = sc.nextInt(); tk sc.nextInt() sc.nextInt sc int at = sc.nextInt(); at sc.nextInt() sc.nextInt sc int ak = sc.nextInt(); ak sc.nextInt() sc.nextInt sc while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        } true {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        } at -= tk at tk if(at <= 0) {
                System.out.println("Yes");
                return;
            } at <= 0 at 0 {
                System.out.println("Yes");
                return;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" return; tt -= ak tt ak if(tt <= 0) {
                System.out.println("No");
                return;
            } tt <= 0 tt 0 {
                System.out.println("No");
                return;
            } System.out.println("No") System.out.println System.out System System.out "No" return; String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tt = sc.nextInt();
        int tk = sc.nextInt();
        int at = sc.nextInt();
        int ak = sc.nextInt();
        while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tt = sc.nextInt();
        int tk = sc.nextInt();
        int at = sc.nextInt();
        int ak = sc.nextInt();
        while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int tt = sc.nextInt();
        int tk = sc.nextInt();
        int at = sc.nextInt();
        int ak = sc.nextInt();
        while(true) {
            at -= tk;
            if(at <= 0) {
                System.out.println("Yes");
                return;
            }
            tt -= ak;
            if(tt <= 0) {
                System.out.println("No");
                return;
            }
        }
    }
}