""" prob_0063.py """

# usage: python3 prob_0063.py


def count(num):
    """ x ** num has num digits """
    output = 0
    i = 1
    while True:
        size = len(str(i ** num))
        if size == num:
            output += 1
        if size > num:
            break
        i += 1

    return output


def solve():
    """ let's go! """
    total = 0
    i = 1
    while (n := count(i)) > 0:
        total += n
        i += 1

    return total


if __name__ == '__main__':
    print(solve())