a = gets.chomp.chars
count = 0
(a.length - 1).downto(0) do |i|
    count += 1 if a[i] =~ /[0-9]/
    if count == 3 and i - 1 > 0 
        a[i + 1..a.length] = a[i..a.length - 1]
        a[i] = ","
        count = 0
    end
end
puts a.join