def potencies_1 (x, maxim):
    n = 1
    suma = 0
    comp = 0
    while n <= maxim:
        suma = suma + n
        comp = comp + 1
        n = n * x
    return suma/comp
    
def potencies_2 (x, maxim, d):
    n = 1
    while n < maxim:
        if n%10 == d:
            return n
        n = n * x
    return -1