batteries = []

with open("day3/input.txt") as file:
    for line in file:
        batteries.append([int(c) for c in line.strip()])


def max_12_digit_number(digits):
    target_len = 12
    to_remove = len(digits) - target_len
    stack = []

    for d in digits:
        while stack and to_remove > 0 and stack[-1] < d:
            stack.pop()
            to_remove -= 1
        stack.append(d)

    # Falls noch nicht genug entfernt wurde (am Ende nur große Zahlen)
    return stack[:target_len]


total = 0

for bank in batteries:
    best_digits = max_12_digit_number(bank)
    joltage = int("".join(map(str, best_digits)))
    total += joltage

print(total)