n = int(input())
if n > 100000:
    print(0.999999999)
    exit()

dp = [0.0] * (1 << 6)
dp[0] = 1.0
for _ in range(n):
    newDP = [0.0] * (1 << 6)
    for S in reversed(range(1 << 6)):
        for i in range(6):
            if (S >> i) & 1:
                newDP[S] += dp[S] / 6.0
            else:
                newDP[S ^ (1 << i)] += dp[S] / 6.0
    dp = newDP

print("{:.15f}".format(dp[(1 << 6)-1]))