n=int(input())

dp=[[0]*7 for i in range(n+1)]
dp[0][0] = 1

for i in range(n):
    for j in range(7):
        dp[i+1][j] += dp[i][j] * (j / 6)
        if j < 6:
            dp[i+1][j+1] += dp[i][j] * ((6-j)/6)

print(dp[n][6])