fun main() {
    val (n, m, k) = readInts()
    val s = readLongs().sortedDescending()
    println(s.take(m + k).sum() * 100.0 / s.sum())
}

private fun readLn() = readLine()!!
private fun readInt() = readLn().toInt()
private fun readLongs() = readStrings().map { it.toLong() }
private fun readStrings() = readLn().split(" ")
private fun readInts() = readStrings().map { it.toInt() }