#!/usr/bin/env ruby
# frozen_string_literal: true

i = ARGF.read.split.map { |w| w.downcase.match('[a-z]+') unless nil? }.compact
c = 0.upto(i.count-3).map { |r| i[r, 3].join ' ' }.sort
t = Hash.new(0);c.each { |p|  t[p] += 1 }
t.sort_by { |k, v| -v }[0..99].each { |c| puts c.reverse.join ' - ' }