def array10 (array):
    if (len(array) == 1):
        return False
    if (array[0]*10 == array[1]):
        return True
    return (array10(array[1:]))

def allStar(line):
    if (len(line) == 1):
        return (line)
    x = line[0]
    return (x + '*'+allStar(line[1:]))

def changePi(line):
    if (len(line) < 2):
        return line

    x = line[0]
    y = line[1]

    if (x == 'p' and y == 'i'):
        return ('3.14'+changePi(line[2:]))

    return (x+changePi(line[1:]))

def harmonicsum (x):
    if (x<1):
        return None
    if (x == 1):
        return 1
    return (1/x + harmonicsum(x-1))