#!/usr/bin/env python
# 2024 - Advent Of Code 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")]

safe = 0
for reports in input_lines:
    levels = [ int(r) for r in reports.split(' ') ]
    # print(f'{levels=}')

    s_diff = 0 if levels[0] > levels[1] else 1
    break_diff = False
    for l in range(1, len(levels)):
        diff = levels[l] - levels[l-1]
        if abs(diff) > 3 or diff == 0:
            break_diff = True
            break
        s_diff2 = 0 if levels[l] < levels[l-1] else 1
        if s_diff ^ s_diff2 != 0:
            # print("sign change")
            break_diff = True
            break
    if not break_diff:
        # print("safe")
        safe += 1

print(f'{safe=}')