using System;
namespace ConsoleApp1
{
class Program
{
public static int F (int c)
{
int d = 1;
for (int i = 1; i <= c; i++)
{
d *= i;
}
return d;
}
static void Main(string[] args)
{
double s = 0;
for (int i = 1; i < 7; i++) {
s += Math.Pow(-1, i) * Math.Pow(5, i) / F(i);
}
Console.WriteLine(s);
}
}
}