import sequtils,strutils,math
var
    N = stdin.readline.parseInt
    A,S : array[0..6, float64]
for i in 1..6:
    A[i] = pow((6 - i) / 6, N.float64) * binom(6, i).float64
    if (1 and i) == 0:
        A[i] *= -1
    S[i] = S[i - 1] + A[i]
echo formatBiggestFloat(1 - S[6], ffDecimal)