import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int x = sc.nextInt();
        int k = sc.nextInt();
        int t = k;
        int b = x;

        while(x < n){
            x += b;
            k += t;

        }
        System.out.println(k);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int x = sc.nextInt();
        int k = sc.nextInt();
        int t = k;
        int b = x;

        while(x < n){
            x += b;
            k += t;

        }
        System.out.println(k);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int x = sc.nextInt();
        int k = sc.nextInt();
        int t = k;
        int b = x;

        while(x < n){
            x += b;
            k += t;

        }
        System.out.println(k);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int x = sc.nextInt();
        int k = sc.nextInt();
        int t = k;
        int b = x;

        while(x < n){
            x += b;
            k += t;

        }
        System.out.println(k);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int x = sc.nextInt(); x sc.nextInt() sc.nextInt sc int k = sc.nextInt(); k sc.nextInt() sc.nextInt sc int t = k; t k int b = x; b x while(x < n){
            x += b;
            k += t;

        } x < n x n {
            x += b;
            k += t;

        } x += b x b k += t k t System.out.println(k) System.out.println System.out System System.out k String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int x = sc.nextInt();
        int k = sc.nextInt();
        int t = k;
        int b = x;

        while(x < n){
            x += b;
            k += t;

        }
        System.out.println(k);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int x = sc.nextInt();
        int k = sc.nextInt();
        int t = k;
        int b = x;

        while(x < n){
            x += b;
            k += t;

        }
        System.out.println(k);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int x = sc.nextInt();
        int k = sc.nextInt();
        int t = k;
        int b = x;

        while(x < n){
            x += b;
            k += t;

        }
        System.out.println(k);
    }
}