#!/usr/bin/env python
# 2024 - Advent Of Code 2 - part 2

# file = 'input_example.txt'
file = 'input.txt'

# pylint: disable=consider-using-with
input_lines = [line.strip('\n') for line in open(file, encoding="utf-8")]


def is_safe(levels):
    s_diff = 0 if levels[0] > levels[1] else 1

    for l in range(1, len(levels)):
        diff = levels[l] - levels[l - 1]
        if abs(diff) > 3 or diff == 0:
            return False

        s_diff2 = 0 if levels[l] < levels[l - 1] else 1
        if s_diff ^ s_diff2 != 0:
            # print("sign change")
            return False

    return True

safe = 0
for reports in input_lines:
    list_levels = [ int(r) for r in reports.split(' ') ]

    if is_safe(list_levels):
        safe += 1
    else:
        for try_level in range(0, len(list_levels)):
            new_levels = list_levels.copy()
            del new_levels[try_level]
            if is_safe(new_levels):
                safe += 1
                break

print(f'{safe=}')