<?php

$numbers = array_map('intval', explode("\n", file_get_contents('input.txt')));

$current_slice = array_sum(array_slice($numbers, 0, 3));

$count = 0;

for ($i = 1, $l = count($numbers) - 3; $i <= $l; $i++) {
    $new_slice = array_sum(array_slice($numbers, $i, 3));
    if ($new_slice > $current_slice) {
        $count++;
    }

    $current_slice = $new_slice;
}

echo $count;