import java.util.*;

public class Main {

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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double want = sc.nextInt();
		double can = sc.nextInt();
		double min = sc.nextInt();
		double bakeNum = Math.ceil(want / can) ;
		System.out.println((int)(bakeNum * min));
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double want = sc.nextInt();
		double can = sc.nextInt();
		double min = sc.nextInt();
		double bakeNum = Math.ceil(want / can) ;
		System.out.println((int)(bakeNum * min));
	} main {
		Scanner sc = new Scanner(System.in);
		double want = sc.nextInt();
		double can = sc.nextInt();
		double min = sc.nextInt();
		double bakeNum = Math.ceil(want / can) ;
		System.out.println((int)(bakeNum * min));
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) double want = sc.nextInt(); want sc.nextInt() sc.nextInt sc double can = sc.nextInt(); can sc.nextInt() sc.nextInt sc double min = sc.nextInt(); min sc.nextInt() sc.nextInt sc double bakeNum = Math.ceil(want / can) ; bakeNum Math.ceil(want / can) Math.ceil Math want / can want can System.out.println((int)(bakeNum * min)) System.out.println System.out System System.out (int)(bakeNum * min) bakeNum min String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double want = sc.nextInt();
		double can = sc.nextInt();
		double min = sc.nextInt();
		double bakeNum = Math.ceil(want / can) ;
		System.out.println((int)(bakeNum * min));
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double want = sc.nextInt();
		double can = sc.nextInt();
		double min = sc.nextInt();
		double bakeNum = Math.ceil(want / can) ;
		System.out.println((int)(bakeNum * min));
	}
} Main
import java.util.*;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double want = sc.nextInt();
		double can = sc.nextInt();
		double min = sc.nextInt();
		double bakeNum = Math.ceil(want / can) ;
		System.out.println((int)(bakeNum * min));
	}
}