import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        int numberOf = input.nextInt();
        int numberAtATime = input.nextInt();
        double timeToMake = input.nextInt();
        double timeToMake2;
        double timeToMake3;


        timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake;
        if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        int numberOf = input.nextInt();
        int numberAtATime = input.nextInt();
        double timeToMake = input.nextInt();
        double timeToMake2;
        double timeToMake3;


        timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake;
        if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        }
    }
} Main public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        int numberOf = input.nextInt();
        int numberAtATime = input.nextInt();
        double timeToMake = input.nextInt();
        double timeToMake2;
        double timeToMake3;


        timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake;
        if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        }
    } main {

        Scanner input = new Scanner(System.in);
        int numberOf = input.nextInt();
        int numberAtATime = input.nextInt();
        double timeToMake = input.nextInt();
        double timeToMake2;
        double timeToMake3;


        timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake;
        if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        }
    } Scanner input = new Scanner(System.in); input new Scanner(System.in) int numberOf = input.nextInt(); numberOf input.nextInt() input.nextInt input int numberAtATime = input.nextInt(); numberAtATime input.nextInt() input.nextInt input double timeToMake = input.nextInt(); timeToMake input.nextInt() input.nextInt input double timeToMake2; timeToMake2 double timeToMake3; timeToMake3 timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake timeToMake3 timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake timeToMake * Math.floor(numberOf / numberAtATime) timeToMake Math.floor(numberOf / numberAtATime) Math.floor Math numberOf / numberAtATime numberOf numberAtATime timeToMake if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        } numberOf % numberAtATime == 0 numberOf % numberAtATime numberOf numberAtATime 0 {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        } timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime) timeToMake2 timeToMake * Math.floor(numberOf / numberAtATime) timeToMake Math.floor(numberOf / numberAtATime) Math.floor Math numberOf / numberAtATime numberOf numberAtATime System.out.print((int)timeToMake2) System.out.print System.out System System.out (int)timeToMake2 {
            System.out.println((int)timeToMake3);
        } System.out.println((int)timeToMake3) System.out.println System.out System System.out (int)timeToMake3 String[] args args public class Main {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        int numberOf = input.nextInt();
        int numberAtATime = input.nextInt();
        double timeToMake = input.nextInt();
        double timeToMake2;
        double timeToMake3;


        timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake;
        if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        }
    }
} public class Main {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        int numberOf = input.nextInt();
        int numberAtATime = input.nextInt();
        double timeToMake = input.nextInt();
        double timeToMake2;
        double timeToMake3;


        timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake;
        if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        int numberOf = input.nextInt();
        int numberAtATime = input.nextInt();
        double timeToMake = input.nextInt();
        double timeToMake2;
        double timeToMake3;


        timeToMake3 = timeToMake * Math.floor(numberOf / numberAtATime) + timeToMake;
        if (numberOf % numberAtATime == 0)
        {
            timeToMake2 = timeToMake * Math.floor(numberOf / numberAtATime);
            System.out.print((int)timeToMake2);
        }
        else {
            System.out.println((int)timeToMake3);
        }
    }
}