N = int(input())

dp = [0] * (1 << 6)
prob = 1/6
dp[0] = 1
for _ in range(N):
    pp = [0] * (1 << 6)
    dp, pp = pp, dp
    for b in range(1 << 6):
        if pp[b] == 0: continue
        for k in range(6):
            nb = b | (1 << k)
            dp[nb] += pp[b] * prob

b = (1 << 6) - 1
ans = dp[b]
print(ans)