

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public final class Main {

    public static void main(String[] args) {
        final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        String[] line = in.nextLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int x = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        int full = n / x + (n % x != 0 ? 1 : 0);
        System.out.println(full * t);
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Scanner; Scanner java.util public final class Main {

    public static void main(String[] args) {
        final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        String[] line = in.nextLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int x = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        int full = n / x + (n % x != 0 ? 1 : 0);
        System.out.println(full * t);
    }
} Main public static void main(String[] args) {
        final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        String[] line = in.nextLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int x = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        int full = n / x + (n % x != 0 ? 1 : 0);
        System.out.println(full * t);
    } main {
        final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        String[] line = in.nextLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int x = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        int full = n / x + (n % x != 0 ? 1 : 0);
        System.out.println(full * t);
    } final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in))); in new Scanner(new BufferedReader(new InputStreamReader(System.in))) String[] line = in.nextLine().split(" "); line in.nextLine().split(" ") in.nextLine().split in.nextLine() in.nextLine in " " int n = Integer.parseInt(line[0]); n Integer.parseInt(line[0]) Integer.parseInt Integer line[0] line 0 int x = Integer.parseInt(line[1]); x Integer.parseInt(line[1]) Integer.parseInt Integer line[1] line 1 int t = Integer.parseInt(line[2]); t Integer.parseInt(line[2]) Integer.parseInt Integer line[2] line 2 int full = n / x + (n % x != 0 ? 1 : 0); full n / x + (n % x != 0 ? 1 : 0) n / x n x (n % x != 0 ? 1 : 0) n % x != 0 n % x n x 0 1 0 System.out.println(full * t) System.out.println System.out System System.out full * t full t String[] args args public final class Main {

    public static void main(String[] args) {
        final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        String[] line = in.nextLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int x = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        int full = n / x + (n % x != 0 ? 1 : 0);
        System.out.println(full * t);
    }
} public final class Main {

    public static void main(String[] args) {
        final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        String[] line = in.nextLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int x = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        int full = n / x + (n % x != 0 ? 1 : 0);
        System.out.println(full * t);
    }
} Main


import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public final class Main {

    public static void main(String[] args) {
        final Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        String[] line = in.nextLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int x = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        int full = n / x + (n % x != 0 ? 1 : 0);
        System.out.println(full * t);
    }
}
