#!/usr/bin/env python3

import sys

input_file = sys.argv[1]

with open(input_file) as fd:
    lines = [line.rstrip() for line in fd.readlines()]


safe_num = 0
for line in lines:
    report = [int(level) for level in line.split(" ")]
    acc = sorted(report)
    dec = acc[::-1]
    if report != acc and report != dec:
        continue
    for i in range(len(report)-1):
        diff = abs(report[i] - report[i+1])
        if diff < 1 or diff > 3:
            break
    else:
        safe_num += 1
print(safe_num)