STDIN.set_encoding 'utf-8'
STDOUT.set_encoding 'utf-8'
def output(key, val)
puts "#{key}\t#{val}"
end
prev_key = nil
sum = 0
while line = STDIN.gets
key, val = line.strip.split /\t/
if key != prev_key && sum > 0
output prev_key, sum
prev_key = key
sum = 0
elsif !prev_key
prev_key = key
end
sum += val.to_i
end
output prev_key, sum