N=int(input())

DP=[0]*7
DP[0]=1

P=[r/6 for r in range(7)]

for _ in range(N):
    for k in range(6,0,-1):
        DP[k]=DP[k]*P[k]+DP[k-1]*(1-P[k-1])

    if DP[0]:
        DP[0]=0

print(DP[6])