Решение

import java.io.BufferedReader
import java.io.BufferedWriter
import java.io.InputStreamReader
import java.io.OutputStreamWriter

fun main() {
    val reader = BufferedReader(InputStreamReader(System.`in`))
    val writer = BufferedWriter(OutputStreamWriter(System.out))
    val (n, k, m) = reader.readLine().split(" ").map(String::toInt)

    if (m > k) {
        writer.write("0")
        reader.close()
        writer.flush()
        writer.close()
        return
    }

    var totalMetal = n
    var totalDetails = 0

    while (totalMetal >= k) {
        val blanks = totalMetal / k
        totalMetal %= k

        val details = (k / m) * blanks
        val leftover = (k % m) * blanks

        totalDetails += details
        totalMetal += leftover
    }

    writer.write(totalDetails.toString())

    reader.close()
    writer.flush()
    writer.close()
}