from string import digits, ascii_lowercase


def from_n_to_10(num: str, base: int = 2):
    alphabet = digits+ascii_lowercase
    assert base in range(2, 10+len(alphabet) + 1)
    res = 0
    for i in num:
        digit = alphabet.index(i)
        assert digit < base
        res = res*base + digit
    return res


print(from_n_to_10(input()))