Final Price with Prime Discount

You are given an integer \( M \) representing the cost of a meal (in dollars). Your task is to calculate the final price that Divya has to pay after applying a discount if applicable. The discount is applied only if \( M \) is a prime number. If \( M \) is prime, a 20% discount is applied, otherwise no discount is given.

The final price should be rounded to two decimal places.

Input

A single integer \( M \) representing the cost of the meal.

Output

A single line containing the final price, rounded to two decimal places.

Note: Use the following formula if \( M \) is prime:

[ \text{Final Price} = 0.80 \times M ]

If \( M \) is not prime, the final price is simply \( M \).

inputFormat

The input consists of a single integer \( M \) (\( 1 \leq M \leq 10^6 \)), representing the cost of the meal.

outputFormat

Output a single line with the final price after discount (if any), rounded to two decimal places.

## sample

17

13.60