import sys
import math
import bisect
from heapq import heapify, heappop, heappush
from collections import deque, defaultdict, Counter
from functools import lru_cache
from itertools import accumulate, combinations, permutations, product

sys.set_int_max_str_digits(10 ** 6)
sys.setrecursionlimit(1000000)
MOD = 10 ** 9 + 7
MOD99 = 998244353

input = lambda: sys.stdin.readline().strip()
NI = lambda: int(input())
NMI = lambda: map(int, input().split())
NLI = lambda: list(NMI())
SI = lambda: input()
SMI = lambda: input().split()
SLI = lambda: list(SMI())
EI = lambda m: [NLI() for _ in range(m)]


def main():
    N = NI()
    C_99_5 = 99 * 98 * 97 * 96 * 95 // 120
    C_N_5 = N * (N-1) * (N-2) * (N-3) * (N-4) // 120
    ans = 12 * C_N_5 / C_99_5
    print(ans)



if __name__ == "__main__":
    main()