fun main(args: Array<String>) {
    val input = readLine()!!
    val result: MutableList<Char> = input.toMutableList()

    for (i in result.indices) {
        if (result[i].isLowerCase()) {
            val changeUpperCase = result[i].toUpperCase()
            result[i] = changeUpperCase
        } else if (result[i].isUpperCase()) {
            val changeLowerCase = result[i].toLowerCase()
            result[i] = changeLowerCase
        }
    }
    println(result.joinToString(""))
}