import java.io.*;

class Main {
    BufferedReader bf;
    PrintWriter writer;
    StringBuilder sb;
    static boolean local_system = false;

    void run() throws IOException {
        int[] c = ni();
        int d = c[0] % c[1] == 0 ? c[0] / c[1] : c[0] / c[1] + 1;
        writer.println(d*c[2]);
    }

    public static void main(String[] args) throws IOException {
        long start_time = System.currentTimeMillis();
        Main obj = new Main();
        obj.run();
        long end_time = System.currentTimeMillis();
        if (local_system) obj.writer.println("Time : " + (end_time - start_time));
        obj.close();
    }

    public Main(){
        writer = new PrintWriter(System.out);
        bf = new BufferedReader(new InputStreamReader(System.in));
        sb = new StringBuilder();
    }

    public int i() throws IOException {
        return Integer.parseInt(bf.readLine());
    }

    public long l() throws IOException {
        return Long.parseLong(bf.readLine());
    }

    public int[] ni() throws IOException {
        String[] data = bf.readLine().split(" ");
        int[] send = new int[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Integer.parseInt(data[i]);
        return send;
    }

    public long[] nl() throws IOException {
        String[] data = bf.readLine().split(" ");
        long[] send = new long[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Long.parseLong(data[i]);
        return send;
    }

    public void close() throws IOException{
        writer.flush();
        writer.close();
        bf.close();
    }
}

 import java.io.*; io.* java class Main {
    BufferedReader bf;
    PrintWriter writer;
    StringBuilder sb;
    static boolean local_system = false;

    void run() throws IOException {
        int[] c = ni();
        int d = c[0] % c[1] == 0 ? c[0] / c[1] : c[0] / c[1] + 1;
        writer.println(d*c[2]);
    }

    public static void main(String[] args) throws IOException {
        long start_time = System.currentTimeMillis();
        Main obj = new Main();
        obj.run();
        long end_time = System.currentTimeMillis();
        if (local_system) obj.writer.println("Time : " + (end_time - start_time));
        obj.close();
    }

    public Main(){
        writer = new PrintWriter(System.out);
        bf = new BufferedReader(new InputStreamReader(System.in));
        sb = new StringBuilder();
    }

    public int i() throws IOException {
        return Integer.parseInt(bf.readLine());
    }

    public long l() throws IOException {
        return Long.parseLong(bf.readLine());
    }

    public int[] ni() throws IOException {
        String[] data = bf.readLine().split(" ");
        int[] send = new int[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Integer.parseInt(data[i]);
        return send;
    }

    public long[] nl() throws IOException {
        String[] data = bf.readLine().split(" ");
        long[] send = new long[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Long.parseLong(data[i]);
        return send;
    }

    public void close() throws IOException{
        writer.flush();
        writer.close();
        bf.close();
    }
} Main BufferedReader bf; bf PrintWriter writer; writer StringBuilder sb; sb static boolean local_system = false; local_system false void run() throws IOException {
        int[] c = ni();
        int d = c[0] % c[1] == 0 ? c[0] / c[1] : c[0] / c[1] + 1;
        writer.println(d*c[2]);
    } run {
        int[] c = ni();
        int d = c[0] % c[1] == 0 ? c[0] / c[1] : c[0] / c[1] + 1;
        writer.println(d*c[2]);
    } int[] c = ni(); c ni() ni int d = c[0] % c[1] == 0 ? c[0] / c[1] : c[0] / c[1] + 1; d c[0] % c[1] == 0 ? c[0] / c[1] : c[0] / c[1] + 1 c[0] % c[1] == 0 c[0] % c[1] c[0] c 0 c[1] c 1 0 c[0] / c[1] c[0] c 0 c[1] c 1 c[0] / c[1] + 1 c[0] / c[1] c[0] c 0 c[1] c 1 1 writer.println(d*c[2]) writer.println writer d*c[2] d c[2] c 2 public static void main(String[] args) throws IOException {
        long start_time = System.currentTimeMillis();
        Main obj = new Main();
        obj.run();
        long end_time = System.currentTimeMillis();
        if (local_system) obj.writer.println("Time : " + (end_time - start_time));
        obj.close();
    } main {
        long start_time = System.currentTimeMillis();
        Main obj = new Main();
        obj.run();
        long end_time = System.currentTimeMillis();
        if (local_system) obj.writer.println("Time : " + (end_time - start_time));
        obj.close();
    } long start_time = System.currentTimeMillis(); start_time System.currentTimeMillis() System.currentTimeMillis System Main obj = new Main(); obj new Main() obj.run() obj.run obj long end_time = System.currentTimeMillis(); end_time System.currentTimeMillis() System.currentTimeMillis System if (local_system) obj.writer.println("Time : " + (end_time - start_time)); local_system obj.writer.println("Time : " + (end_time - start_time)) obj.writer.println obj.writer obj obj.writer "Time : " + (end_time - start_time) "Time : " (end_time - start_time) end_time start_time obj.close() obj.close obj String[] args args public Main(){
        writer = new PrintWriter(System.out);
        bf = new BufferedReader(new InputStreamReader(System.in));
        sb = new StringBuilder();
    } Main {
        writer = new PrintWriter(System.out);
        bf = new BufferedReader(new InputStreamReader(System.in));
        sb = new StringBuilder();
    } writer = new PrintWriter(System.out) writer new PrintWriter(System.out) bf = new BufferedReader(new InputStreamReader(System.in)) bf new BufferedReader(new InputStreamReader(System.in)) sb = new StringBuilder() sb new StringBuilder() public int i() throws IOException {
        return Integer.parseInt(bf.readLine());
    } i {
        return Integer.parseInt(bf.readLine());
    } return Integer.parseInt(bf.readLine()); Integer.parseInt(bf.readLine()) Integer.parseInt Integer bf.readLine() bf.readLine bf public long l() throws IOException {
        return Long.parseLong(bf.readLine());
    } l {
        return Long.parseLong(bf.readLine());
    } return Long.parseLong(bf.readLine()); Long.parseLong(bf.readLine()) Long.parseLong Long bf.readLine() bf.readLine bf public int[] ni() throws IOException {
        String[] data = bf.readLine().split(" ");
        int[] send = new int[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Integer.parseInt(data[i]);
        return send;
    } ni {
        String[] data = bf.readLine().split(" ");
        int[] send = new int[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Integer.parseInt(data[i]);
        return send;
    } String[] data = bf.readLine().split(" "); data bf.readLine().split(" ") bf.readLine().split bf.readLine() bf.readLine bf " " int[] send = new int[data.length]; send new int[data.length] data.length data data.length for (int i = 0, h = data.length; i < h; i++) send[i] = Integer.parseInt(data[i]); int i = 0, h = data.length; int i = 0 i 0 h = data.length; h data.length data data.length i < h i h i++ i++ i send[i] = Integer.parseInt(data[i]); send[i] = Integer.parseInt(data[i]) send[i] send i Integer.parseInt(data[i]) Integer.parseInt Integer data[i] data i return send; send public long[] nl() throws IOException {
        String[] data = bf.readLine().split(" ");
        long[] send = new long[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Long.parseLong(data[i]);
        return send;
    } nl {
        String[] data = bf.readLine().split(" ");
        long[] send = new long[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Long.parseLong(data[i]);
        return send;
    } String[] data = bf.readLine().split(" "); data bf.readLine().split(" ") bf.readLine().split bf.readLine() bf.readLine bf " " long[] send = new long[data.length]; send new long[data.length] data.length data data.length for (int i = 0, h = data.length; i < h; i++) send[i] = Long.parseLong(data[i]); int i = 0, h = data.length; int i = 0 i 0 h = data.length; h data.length data data.length i < h i h i++ i++ i send[i] = Long.parseLong(data[i]); send[i] = Long.parseLong(data[i]) send[i] send i Long.parseLong(data[i]) Long.parseLong Long data[i] data i return send; send public void close() throws IOException{
        writer.flush();
        writer.close();
        bf.close();
    } close {
        writer.flush();
        writer.close();
        bf.close();
    } writer.flush() writer.flush writer writer.close() writer.close writer bf.close() bf.close bf
import java.io.*;

class Main {
    BufferedReader bf;
    PrintWriter writer;
    StringBuilder sb;
    static boolean local_system = false;

    void run() throws IOException {
        int[] c = ni();
        int d = c[0] % c[1] == 0 ? c[0] / c[1] : c[0] / c[1] + 1;
        writer.println(d*c[2]);
    }

    public static void main(String[] args) throws IOException {
        long start_time = System.currentTimeMillis();
        Main obj = new Main();
        obj.run();
        long end_time = System.currentTimeMillis();
        if (local_system) obj.writer.println("Time : " + (end_time - start_time));
        obj.close();
    }

    public Main(){
        writer = new PrintWriter(System.out);
        bf = new BufferedReader(new InputStreamReader(System.in));
        sb = new StringBuilder();
    }

    public int i() throws IOException {
        return Integer.parseInt(bf.readLine());
    }

    public long l() throws IOException {
        return Long.parseLong(bf.readLine());
    }

    public int[] ni() throws IOException {
        String[] data = bf.readLine().split(" ");
        int[] send = new int[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Integer.parseInt(data[i]);
        return send;
    }

    public long[] nl() throws IOException {
        String[] data = bf.readLine().split(" ");
        long[] send = new long[data.length];
        for (int i = 0, h = data.length; i < h; i++) send[i] = Long.parseLong(data[i]);
        return send;
    }

    public void close() throws IOException{
        writer.flush();
        writer.close();
        bf.close();
    }
}


