#!/usr/bin/env ruby1.9.1


shard_count_key = "__SHARD_COUNT__"

STDIN.set_encoding 'utf-8'
STDOUT.set_encoding 'utf-8'

w = {}
c = {}
w.default = 0
c.default = 0
while line = STDIN.gets
  key, val = line.split /\t/
  w[key] += val.to_f
  c[key] += 1
end

puts "# dtrain reducer: active on all"
shard_count = w["__SHARD_COUNT__"]
puts "shard count #{shard_count}"
w.each_key { |k|
  if k == shard_count_key then next end
  if c[k] == shard_count then puts "#{k}\t#{w[k]/shard_count}" end
}