import java.util.Scanner;

public class No3511 {
	
	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		int A = Integer.parseInt(scanner.next());
		int B = Integer.parseInt(scanner.next());
		
		int C = Integer.parseInt(scanner.next());
		int D = Integer.parseInt(scanner.next());
		
		int S = Integer.parseInt(scanner.next());
		
		if(A*C + B*D > S) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
		
		scanner.close();

	}

}