Triangle
A talented student, inspired by the Pythagorean theorem, drew N right-angled triangles on the board before the next class. At the beginning of the lesson, the teacher measured the sides of these triangles using a wooden ruler, rounding each measurement to the nearest whole centimeter, and noted these numbers down in a notebook. Then, after covering the board, the teacher read out these recorded numbers in a random order and challenged the class to determine how many right-angled triangles the "Pythagorean student" had actually drawn.
Input
The input file starts with the number N (3 ≤ N ≤ 100) on the first line, followed by 3·N lines, each containing a single natural number (a ≤ 2147483647).
Output
The output file should contain a single line with the integer k — the maximum number of right-angled triangles that can be formed from the given side lengths.