import java.util.Scanner;

public class Main {
	static int N;
	static int X;
	static int T;
	public static void main(String args[]) {
		try(Scanner sc = new Scanner(System.in)){
			N = Integer.parseInt(sc.next());
			X = Integer.parseInt(sc.next());
			T = Integer.parseInt(sc.next());
		}
		int count=0;
		for(int i=0;N>X*i;i++) {
			count++;
		}
		if(count==0) {
			System.out.println(1);
		}else {			
			System.out.println(count*T);
		}
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz