n = int(input())

m = 2**6

dp = [[0 for i in range(m)] for j in range(n+1)]
dp[0][0] = 1

for i in range(1, n+1):
    
    for j in range(m):
        for k in range(6):
            k = 2**k
            dp[i][j | k] += dp[i-1][j] / 6

print(dp[-1][-1])