import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        String result = "Yes";

        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);

        while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        }
        if (c > 0) {
            result = "No";
        }

        System.out.println(result);
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        String result = "Yes";

        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);

        while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        }
        if (c > 0) {
            result = "No";
        }

        System.out.println(result);
    }
} Main public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        String result = "Yes";

        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);

        while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        }
        if (c > 0) {
            result = "No";
        }

        System.out.println(result);
    } main {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        String result = "Yes";

        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);

        while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        }
        if (c > 0) {
            result = "No";
        }

        System.out.println(result);
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String[] str = br.readLine().split(" "); str br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " String result = "Yes"; result "Yes" int a = Integer.parseInt(str[0]); a Integer.parseInt(str[0]) Integer.parseInt Integer str[0] str 0 int b = Integer.parseInt(str[1]); b Integer.parseInt(str[1]) Integer.parseInt Integer str[1] str 1 int c = Integer.parseInt(str[2]); c Integer.parseInt(str[2]) Integer.parseInt Integer str[2] str 2 int d = Integer.parseInt(str[3]); d Integer.parseInt(str[3]) Integer.parseInt Integer str[3] str 3 while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        } a > 0 && c > 0 a > 0 a 0 c > 0 c 0 {
            c -= b;
            a -= d;
        } c -= b c b a -= d a d if (c > 0) {
            result = "No";
        } c > 0 c 0 {
            result = "No";
        } result = "No" result "No" System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        String result = "Yes";

        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);

        while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        }
        if (c > 0) {
            result = "No";
        }

        System.out.println(result);
    }
} public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        String result = "Yes";

        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);

        while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        }
        if (c > 0) {
            result = "No";
        }

        System.out.println(result);
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] str = br.readLine().split(" ");
        String result = "Yes";

        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);

        while (a > 0 && c > 0) {
            c -= b;
            a -= d;
        }
        if (c > 0) {
            result = "No";
        }

        System.out.println(result);
    }
}
