
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.annotation.Target;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.FormatFlagsConversionMismatchException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Random;
import java.util.StringTokenizer;

import javax.naming.spi.DirStateFactory.Result;
import javax.swing.text.AbstractDocument.BranchElement;

import org.w3c.dom.css.Counter;
 
public class Main {

	
	public static void main(String[] args) {
		FastScanner fs=new FastScanner();
		int first = fs.nextInt();
		int sec = fs.nextInt();
		int third = fs.nextInt();

		if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		}
	}
	
 
	static final Random random=new Random();
	
	static void ruffleSort(int[] a) {
		int n=a.length;//shuffle, then sort 
		for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		}
		Arrays.sort(a);
	}
	
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		long nextLong() {
			return Long.parseLong(next());
		}
	}
 
	
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.lang.annotation.Target; Target java.lang.annotation import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.FormatFlagsConversionMismatchException; FormatFlagsConversionMismatchException java.util import java.util.HashMap; HashMap java.util import java.util.HashSet; HashSet java.util import java.util.LinkedList; LinkedList java.util import java.util.Queue; Queue java.util import java.util.Random; Random java.util import java.util.StringTokenizer; StringTokenizer java.util import javax.naming.spi.DirStateFactory.Result; Result javax.naming.spi.DirStateFactory import javax.swing.text.AbstractDocument.BranchElement; BranchElement javax.swing.text.AbstractDocument import org.w3c.dom.css.Counter; Counter org.w3c.dom.css public class Main {

	
	public static void main(String[] args) {
		FastScanner fs=new FastScanner();
		int first = fs.nextInt();
		int sec = fs.nextInt();
		int third = fs.nextInt();

		if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		}
	}
	
 
	static final Random random=new Random();
	
	static void ruffleSort(int[] a) {
		int n=a.length;//shuffle, then sort 
		for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		}
		Arrays.sort(a);
	}
	
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		long nextLong() {
			return Long.parseLong(next());
		}
	}
 
	
} Main static final Random random=new Random(); random new Random() public static void main(String[] args) {
		FastScanner fs=new FastScanner();
		int first = fs.nextInt();
		int sec = fs.nextInt();
		int third = fs.nextInt();

		if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		}
	} main {
		FastScanner fs=new FastScanner();
		int first = fs.nextInt();
		int sec = fs.nextInt();
		int third = fs.nextInt();

		if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		}
	} FastScanner fs=new FastScanner(); fs new FastScanner() int first = fs.nextInt(); first fs.nextInt() fs.nextInt fs int sec = fs.nextInt(); sec fs.nextInt() fs.nextInt fs int third = fs.nextInt(); third fs.nextInt() fs.nextInt fs if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		} first%sec==0 first%sec first sec 0 {
			System.out.println((first/sec)*third);
		} System.out.println((first/sec)*third) System.out.println System.out System System.out (first/sec)*third (first/sec) first sec third {
			System.out.println(((first/sec)+1)*third);
		} System.out.println(((first/sec)+1)*third) System.out.println System.out System System.out ((first/sec)+1)*third ((first/sec)+1) (first/sec) first sec 1 third String[] args args static void ruffleSort(int[] a) {
		int n=a.length;//shuffle, then sort 
		for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		}
		Arrays.sort(a);
	} ruffleSort {
		int n=a.length;//shuffle, then sort 
		for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		}
		Arrays.sort(a);
	} int n=a.length; n a.length a a.length for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		} int i=0; int i=0; i 0 i<n i n i++ i++ i {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		} {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		} int oi=random.nextInt(n) oi random.nextInt(n) random.nextInt random n temp=a[oi]; temp a[oi] a oi a[oi]=a[i] a[oi] a oi a[i] a i a[i]=temp a[i] a i temp Arrays.sort(a) Arrays.sort Arrays a int[] a a static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		long nextLong() {
			return Long.parseLong(next());
		}
	} FastScanner BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringTokenizer st=new StringTokenizer(""); st new StringTokenizer("") String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		} next {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		} while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				} !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				} IOException e {
					e.printStackTrace();
				} e.printStackTrace() e.printStackTrace e {
					st=new StringTokenizer(br.readLine());
				} st=new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
			return Integer.parseInt(next());
		} nextInt {
			return Integer.parseInt(next());
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		} readArray {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		} int[] a=new int[n]; a new int[n] n for (int i=0; i<n; i++) a[i]=nextInt(); int i=0; int i=0; i 0 i<n i n i++ i++ i a[i]=nextInt(); a[i]=nextInt() a[i] a i nextInt() nextInt return a; a int n n long nextLong() {
			return Long.parseLong(next());
		} nextLong {
			return Long.parseLong(next());
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {

	
	public static void main(String[] args) {
		FastScanner fs=new FastScanner();
		int first = fs.nextInt();
		int sec = fs.nextInt();
		int third = fs.nextInt();

		if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		}
	}
	
 
	static final Random random=new Random();
	
	static void ruffleSort(int[] a) {
		int n=a.length;//shuffle, then sort 
		for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		}
		Arrays.sort(a);
	}
	
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		long nextLong() {
			return Long.parseLong(next());
		}
	}
 
	
} public class Main {

	
	public static void main(String[] args) {
		FastScanner fs=new FastScanner();
		int first = fs.nextInt();
		int sec = fs.nextInt();
		int third = fs.nextInt();

		if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		}
	}
	
 
	static final Random random=new Random();
	
	static void ruffleSort(int[] a) {
		int n=a.length;//shuffle, then sort 
		for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		}
		Arrays.sort(a);
	}
	
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		long nextLong() {
			return Long.parseLong(next());
		}
	}
 
	
} Main

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.annotation.Target;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.FormatFlagsConversionMismatchException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Random;
import java.util.StringTokenizer;

import javax.naming.spi.DirStateFactory.Result;
import javax.swing.text.AbstractDocument.BranchElement;

import org.w3c.dom.css.Counter;
 
public class Main {

	
	public static void main(String[] args) {
		FastScanner fs=new FastScanner();
		int first = fs.nextInt();
		int sec = fs.nextInt();
		int third = fs.nextInt();

		if(first%sec==0) {
			System.out.println((first/sec)*third);
		}
		else {
			System.out.println(((first/sec)+1)*third);
		}
	}
	
 
	static final Random random=new Random();
	
	static void ruffleSort(int[] a) {
		int n=a.length;//shuffle, then sort 
		for (int i=0; i<n; i++) {
			int oi=random.nextInt(n), temp=a[oi];
			a[oi]=a[i]; a[i]=temp;
		}
		Arrays.sort(a);
	}
	
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		long nextLong() {
			return Long.parseLong(next());
		}
	}
 
	
}