N = int(input())
dp = [1, 0, 0, 0, 0, 0, 0]

for i in range(N):
    next_dp = [0] * 7
    for j in range(1, 7):
        next_dp[j] = dp[j-1] * ((7 - j) / 6) + dp[j] * (j / 6)
    dp = next_dp

ans = dp[6]
print(ans)