import java.util.Scanner;

class Main {
    public static void main(String[] args) {
	Scanner stdIn = new Scanner(System.in);

	int a = stdIn.nextInt();
	int b = stdIn.nextInt();
	int c = stdIn.nextInt();
	int d = stdIn.nextInt();


	int deatht = (a % d == 0) ? a/d : a/d+1;
	int deatha = (c % b == 0) ? c/b : c/b+1;

	System.out.println((deatht < deatha) ? "No" : "Yes");
    }
} import java.util.Scanner; Scanner java.util class Main {
    public static void main(String[] args) {
	Scanner stdIn = new Scanner(System.in);

	int a = stdIn.nextInt();
	int b = stdIn.nextInt();
	int c = stdIn.nextInt();
	int d = stdIn.nextInt();


	int deatht = (a % d == 0) ? a/d : a/d+1;
	int deatha = (c % b == 0) ? c/b : c/b+1;

	System.out.println((deatht < deatha) ? "No" : "Yes");
    }
} Main public static void main(String[] args) {
	Scanner stdIn = new Scanner(System.in);

	int a = stdIn.nextInt();
	int b = stdIn.nextInt();
	int c = stdIn.nextInt();
	int d = stdIn.nextInt();


	int deatht = (a % d == 0) ? a/d : a/d+1;
	int deatha = (c % b == 0) ? c/b : c/b+1;

	System.out.println((deatht < deatha) ? "No" : "Yes");
    } main {
	Scanner stdIn = new Scanner(System.in);

	int a = stdIn.nextInt();
	int b = stdIn.nextInt();
	int c = stdIn.nextInt();
	int d = stdIn.nextInt();


	int deatht = (a % d == 0) ? a/d : a/d+1;
	int deatha = (c % b == 0) ? c/b : c/b+1;

	System.out.println((deatht < deatha) ? "No" : "Yes");
    } Scanner stdIn = new Scanner(System.in); stdIn new Scanner(System.in) int a = stdIn.nextInt(); a stdIn.nextInt() stdIn.nextInt stdIn int b = stdIn.nextInt(); b stdIn.nextInt() stdIn.nextInt stdIn int c = stdIn.nextInt(); c stdIn.nextInt() stdIn.nextInt stdIn int d = stdIn.nextInt(); d stdIn.nextInt() stdIn.nextInt stdIn int deatht = (a % d == 0) ? a/d : a/d+1; deatht (a % d == 0) ? a/d : a/d+1 (a % d == 0) a % d a d 0 a/d a d a/d+1 a/d a d 1 int deatha = (c % b == 0) ? c/b : c/b+1; deatha (c % b == 0) ? c/b : c/b+1 (c % b == 0) c % b c b 0 c/b c b c/b+1 c/b c b 1 System.out.println((deatht < deatha) ? "No" : "Yes") System.out.println System.out System System.out (deatht < deatha) ? "No" : "Yes" (deatht < deatha) deatht deatha "No" "Yes" String[] args args
import java.util.Scanner;

class Main {
    public static void main(String[] args) {
	Scanner stdIn = new Scanner(System.in);

	int a = stdIn.nextInt();
	int b = stdIn.nextInt();
	int c = stdIn.nextInt();
	int d = stdIn.nextInt();


	int deatht = (a % d == 0) ? a/d : a/d+1;
	int deatha = (c % b == 0) ? c/b : c/b+1;

	System.out.println((deatht < deatha) ? "No" : "Yes");
    }
}