
import java.util.*;

public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int th = sc.nextInt();
        int ts = sc.nextInt();
        int ah = sc.nextInt();
        int as = sc.nextInt();

        int turn = 0;
        while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        }

        if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    public static void main(String[] args) {
        new Main().solve();
    }
} import java.util.*; util.* java public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int th = sc.nextInt();
        int ts = sc.nextInt();
        int ah = sc.nextInt();
        int as = sc.nextInt();

        int turn = 0;
        while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        }

        if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    public static void main(String[] args) {
        new Main().solve();
    }
} Main private static final Scanner sc = new Scanner(System.in); sc new Scanner(System.in) private void solve() {
        int th = sc.nextInt();
        int ts = sc.nextInt();
        int ah = sc.nextInt();
        int as = sc.nextInt();

        int turn = 0;
        while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        }

        if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } solve {
        int th = sc.nextInt();
        int ts = sc.nextInt();
        int ah = sc.nextInt();
        int as = sc.nextInt();

        int turn = 0;
        while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        }

        if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } int th = sc.nextInt(); th sc.nextInt() sc.nextInt sc int ts = sc.nextInt(); ts sc.nextInt() sc.nextInt sc int ah = sc.nextInt(); ah sc.nextInt() sc.nextInt sc int as = sc.nextInt(); as sc.nextInt() sc.nextInt sc int turn = 0; turn 0 while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        } th > 0 && ah > 0 th > 0 th 0 ah > 0 ah 0 {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        } if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            } turn == 0 turn 0 {
                ah -= ts;
            } ah -= ts ah ts {
                th -= as;
            } th -= as th as turn ^= 1 turn 1 if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } ah <= 0 ah 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" public static void main(String[] args) {
        new Main().solve();
    } main {
        new Main().solve();
    } new Main().solve() new Main().solve new Main() String[] args args public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int th = sc.nextInt();
        int ts = sc.nextInt();
        int ah = sc.nextInt();
        int as = sc.nextInt();

        int turn = 0;
        while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        }

        if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    public static void main(String[] args) {
        new Main().solve();
    }
} public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int th = sc.nextInt();
        int ts = sc.nextInt();
        int ah = sc.nextInt();
        int as = sc.nextInt();

        int turn = 0;
        while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        }

        if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    public static void main(String[] args) {
        new Main().solve();
    }
} Main

import java.util.*;

public class Main {
    private static final Scanner sc = new Scanner(System.in);

    private void solve() {
        int th = sc.nextInt();
        int ts = sc.nextInt();
        int ah = sc.nextInt();
        int as = sc.nextInt();

        int turn = 0;
        while (th > 0 && ah > 0) {
            if (turn == 0) {
                ah -= ts;
            } else {
                th -= as;
            }
            turn ^= 1;
        }

        if (ah <= 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    public static void main(String[] args) {
        new Main().solve();
    }
}