"""Day 9."""
from itertools import permutations

with open("input") as f:
    nums = [int(x) for x in f.read().rstrip().split("\n")]

preamble_length = 25
invalid_number = None

# Part 1
for idx, val in enumerate(nums[preamble_length:], start=preamble_length):
    pre = nums[idx - preamble_length: idx]
    valid = False
    for combs in permutations(pre, 2):
        if sum(combs) == val:
            valid = True
    if not valid:
        invalid_number = val
        print(invalid_number)
        break

# Part 2
found = False
for x in range(len(nums)):
    for y in range(x + 1, len(nums)):
        subset = nums[x:y]
        total = sum(subset)
        if total > invalid_number:
            break
        if total == invalid_number:
            print(min(subset) + max(subset))
            found = True
            break
    if found:
        break