fun main(args: Array<String>) {
    val (x,y,z) = readLine()!!.split(" ").map { it.toInt() }
    val diff = Math.abs(x-y)
    val ans = if(diff > z) {
        Math.min(x,y) + z
    } else {
        Math.max(x,y) + (z-diff)/2
    }
    println(ans)
}