import java.util.Scanner;

public class Main {
    public int getTime(int n, int x, int t) {
        if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t;
    }

    public static void main(String[] args) throws Exception {
        Main solution = new Main();

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int x = scanner.nextInt();
        int t = scanner.nextInt();

        int answer = solution.getTime(n, x, t);
        System.out.println(answer);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public int getTime(int n, int x, int t) {
        if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t;
    }

    public static void main(String[] args) throws Exception {
        Main solution = new Main();

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int x = scanner.nextInt();
        int t = scanner.nextInt();

        int answer = solution.getTime(n, x, t);
        System.out.println(answer);
    }
} Main public int getTime(int n, int x, int t) {
        if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t;
    } getTime {
        if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t;
    } if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t; n % x == 0 n % x n x 0 return (n / x) * t; (n / x) * t (n / x) n x t return (n / x + 1) * t; (n / x + 1) * t (n / x + 1) n / x n x 1 t int n n int x x int t t public static void main(String[] args) throws Exception {
        Main solution = new Main();

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int x = scanner.nextInt();
        int t = scanner.nextInt();

        int answer = solution.getTime(n, x, t);
        System.out.println(answer);
    } main {
        Main solution = new Main();

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int x = scanner.nextInt();
        int t = scanner.nextInt();

        int answer = solution.getTime(n, x, t);
        System.out.println(answer);
    } Main solution = new Main(); solution new Main() Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int n = scanner.nextInt(); n scanner.nextInt() scanner.nextInt scanner int x = scanner.nextInt(); x scanner.nextInt() scanner.nextInt scanner int t = scanner.nextInt(); t scanner.nextInt() scanner.nextInt scanner int answer = solution.getTime(n, x, t); answer solution.getTime(n, x, t) solution.getTime solution n x t System.out.println(answer) System.out.println System.out System System.out answer String[] args args public class Main {
    public int getTime(int n, int x, int t) {
        if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t;
    }

    public static void main(String[] args) throws Exception {
        Main solution = new Main();

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int x = scanner.nextInt();
        int t = scanner.nextInt();

        int answer = solution.getTime(n, x, t);
        System.out.println(answer);
    }
} public class Main {
    public int getTime(int n, int x, int t) {
        if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t;
    }

    public static void main(String[] args) throws Exception {
        Main solution = new Main();

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int x = scanner.nextInt();
        int t = scanner.nextInt();

        int answer = solution.getTime(n, x, t);
        System.out.println(answer);
    }
} Main
import java.util.Scanner;

public class Main {
    public int getTime(int n, int x, int t) {
        if (n % x == 0) return (n / x) * t;
        else return (n / x + 1) * t;
    }

    public static void main(String[] args) throws Exception {
        Main solution = new Main();

        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int x = scanner.nextInt();
        int t = scanner.nextInt();

        int answer = solution.getTime(n, x, t);
        System.out.println(answer);
    }
}