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);
		}
	}
} import java.util.Scanner; Scanner java.util 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);
		}
	}
} Main static int N; N static int X; X static int T; 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);
		}
	} main {
		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);
		}
	} try(Scanner sc = new Scanner(System.in)){
			N = Integer.parseInt(sc.next());
			X = Integer.parseInt(sc.next());
			T = Integer.parseInt(sc.next());
		} {
			N = Integer.parseInt(sc.next());
			X = Integer.parseInt(sc.next());
			T = Integer.parseInt(sc.next());
		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) N = Integer.parseInt(sc.next()) N Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc X = Integer.parseInt(sc.next()) X Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc T = Integer.parseInt(sc.next()) T Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int count=0; count 0 for(int i=0;N>X*i;i++) {
			count++;
		} int i=0; int i=0; i 0 N>X*i N X*i X i i++ i++ i {
			count++;
		} {
			count++;
		} count++ count if(count==0) {
			System.out.println(1);
		}else {			
			System.out.println(count*T);
		} count==0 count 0 {
			System.out.println(1);
		} System.out.println(1) System.out.println System.out System System.out 1 {			
			System.out.println(count*T);
		} System.out.println(count*T) System.out.println System.out System System.out count*T count T String args[] args 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);
		}
	}
} 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);
		}
	}
} Main
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);
		}
	}
}