import kotlin.math.ceil
import kotlin.math.floor

fun main() {
    val nk = nextIntList()
    val ans = solve(nk)
    println(ans)



}

/**
777...の倍数　→　111...の7倍
 */
fun solve(k: List<Int>): Int {
    val a = ceil(k[0].toDouble() / k[1].toDouble()).toInt()
    return a * k[2]
}


fun mod(k: Int): Int {
    tailrec fun innerFunc(modSum: Int, plainMod: Int, count: Int): Int {
        return if (modSum == 0) {
            count
        } else {
            val newPlainMod = plainMod * 10

            val newModSum = if (modSum + newPlainMod < k) {
                modSum + newPlainMod
            } else {
                (modSum + newPlainMod) % k
            }
            innerFunc(newModSum, newPlainMod, count + 1)
        }
    }
    return innerFunc((1 % k), (1 % k), 1)
}

fun nextInt(): Int {
    return readLine()!!.toInt()
}

fun nextIntList(): List<Int> {
    return readLine()!!.split(" ").map { it.toInt() }
}

fun nextLongList(): List<Long> {
    return readLine()!!.split(" ").map { it.toLong() }
}

fun nextString(): String {
    return readLine()!!
}