import java.util.Scanner;

public class Main{
	public static void main(String[] arjs) {
		Scanner sc =new Scanner(System.in);
		int n =sc.nextInt();
		int a =sc.nextInt();
		int b =sc.nextInt();
		int c =sc.nextInt();
		int e =sc.nextInt();
		int k =n*a;
		if(k>a*e+(b+c)) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
		
	}
}
/**************************************************************
	Problem: 1634
	User: admin
	Language: Java
	Result: Accepted
	Time:391 ms
	Memory:39828 kb
****************************************************************/