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)
