import java.util.Scanner;

class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
      
      	int total = sc.nextInt();
      	int once = sc.nextInt();
      	int time = sc.nextInt();
      	int count = 0;
      
		while(total > 0) {
        	total -= once;
      		count++;    	
        }
      	System.out.println(count * time);
    
    
    }
}
/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