import Foundation

let input_line: String = readLine()!
let split: [String] = input_line.components(separatedBy: " ")
let a = Int(split[0])!
let b = Int(split[1])!
let c = Int(split[2])!

//var takoyaki = 0
//var zikan = 0
//
//while a > takoyaki {
//    takoyaki += b
//    zikan += c
//}
//
//print(zikan)

if (a%b == 0) {
    print(a/b * c)
}else{
    print(a/b * c + 1)
}
