N = int(input())

dp = [0] * 7
# dp[i] : i 面が出ている確率
dp[0] = 1
for _ in range(N):
    pp = [0] * 7
    dp, pp = pp, dp
    for i in range(6):
        # 新しい面が出る確率
        dp[i+1] += pp[i] * (6 - i) / 6
        # 既に出た面が出る確率
        dp[i] += pp[i] * i / 6

    dp[6] += pp[6]

ans = dp[6]
print(ans)