#!/usr/bin/env python3

INPUT_FILE = 'input.txt'

def main():
    reports = [list(map(int, vals.split())) for vals in open(INPUT_FILE, 'r').readlines()]
    safe_reports = 0
    for report in reports:
        ok = all([1 <= abs(report[i] - report[i + 1]) <= 3 for i in range(len(report) - 1 )])
        is_sorted = report == sorted(report) or report == sorted(report, reverse=True)
        if ok and is_sorted: safe_reports += 1

    print(safe_reports)

if __name__ == '__main__':
    main()