fun main(args: Array<String>) {
    val str = readLine()!!
    val length = str.length
    val shift = 3 - length % 3

    print(str[0])
    for (i in 1 until length) {
        if ((i + shift) % 3 == 0) print(",")
        print(str[i])
    }
    print("\n")
}