import java.lang.StringBuilder
import java.util.*

fun main(args: Array<String>) {
    val a = LinkedList<Char>().also { it.addAll(readLine()!!.trim().reversed().toList()) }
    val ans = StringBuilder()
    while (a.isNotEmpty()) {
        if(ans.isNotEmpty()) {
            ans.append(',')
        }
        repeat(3) {
            if(a.isNotEmpty()) {
                ans.append(a.pop())
            }
        }
    }
    println(ans.toString().reversed())
}