from decimal import Decimal, getcontext

getcontext().prec = 200  # Set sufficient precision to handle large exponents

N = int(input())
if N == 0:
    print("4.00000000")
else:
    numerator = 4 * (3 ** N)
    denominator = 4 ** N
    result = Decimal(numerator) / Decimal(denominator)
    print("{0:.8f}".format(result))