# -*- coding: utf-8 -*-
require 'csv'
x, y = [], []
cnt = 0
CSV.foreach("triangles.txt") {|row|
  x = [row[0], row[2], row[4]].map(&:to_i)
  y = [row[1], row[3], row[5]].map(&:to_i)
  cnt += 1 if [x[0]*y[1]-y[0]*x[1],
               x[1]*y[2]-y[1]*x[2],
               x[2]*y[0]-y[2]*x[0]].map {|e| e >= 0 ? true : false }.uniq.size == 1
}
p cnt