import java.util.*;
    public class Main {
        public static void main(String[] args) {
            Scanner sc = new Scanner(System.in);
            double a = sc.nextInt();
            double b = sc.nextInt();
            int c = sc.nextInt();
            double d = Math.ceil(a/b);
            System.out.println((int)d * c);
        }
    }

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz