import java.util.*;
import java.math.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		long n = sc.nextLong();
		long g = sc.nextLong();
		long v = sc.nextLong();
		long total = n/5*g;
		BigDecimal b1 = new BigDecimal(total);
		BigDecimal b2 = new BigDecimal(v);
		BigDecimal ans = b1.divide(b2,9,RoundingMode.HALF_UP);
		System.out.println(ans);
	}
}