# -*- coding: utf-8 -*-
def nCm(n, m):
    A = 1.0
    B = 1.0
    C = n
    D = m
    for i in range(0, m):
        A *= C
        B *= D
        D -= 1
        C -= 1
    return A / B


N = input()
if N < 5:
    print 0
    exit()
print 12.0 * nCm(94, N-5) / nCm(99, N)