

import java.util.*;
import java.io.*;

public class Main {
    static class FS {
        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());
        }

        double nextDouble() {
            return Double.parseDouble(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 long[] readLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    }

    static final FS sc = new FS();
    static final PrintWriter out = new PrintWriter(System.out);
    static final int mod = 1000000007;

    public static void main(String[] args) {

        solve();
        out.close();

    }

    static void solve() {
        int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        }

    }
}

 import java.util.*; util.* java import java.io.*; io.* java public class Main {
    static class FS {
        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());
        }

        double nextDouble() {
            return Double.parseDouble(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 long[] readLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    }

    static final FS sc = new FS();
    static final PrintWriter out = new PrintWriter(System.out);
    static final int mod = 1000000007;

    public static void main(String[] args) {

        solve();
        out.close();

    }

    static void solve() {
        int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        }

    }
} Main static final FS sc = new FS(); sc new FS() static final PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) static final int mod = 1000000007; mod 1000000007 public static void main(String[] args) {

        solve();
        out.close();

    } main {

        solve();
        out.close();

    } solve() solve out.close() out.close out String[] args args static void solve() {
        int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        }

    } solve {
        int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        }

    } int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        } n % a == 0 n % a n a 0 {
            out.println((n / a) * b);
        } out.println((n / a) * b) out.println out (n / a) * b (n / a) n a b {
            out.println(((n / a) * b) + b );
        } out.println(((n / a) * b) + b ) out.println out ((n / a) * b) + b ((n / a) * b) (n / a) n a b b static class FS {
        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());
        }

        double nextDouble() {
            return Double.parseDouble(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 long[] readLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    } FS 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 double nextDouble() {
            return Double.parseDouble(next());
        } nextDouble {
            return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double 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 long[] readLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        } readLongArray {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        } long[] a = new long[n]; a new long[n] n for (int i = 0; i < n; i++)
                a[i] = nextLong(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = nextLong(); a[i] = nextLong() a[i] a i nextLong() nextLong return a; a int n n public class Main {
    static class FS {
        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());
        }

        double nextDouble() {
            return Double.parseDouble(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 long[] readLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    }

    static final FS sc = new FS();
    static final PrintWriter out = new PrintWriter(System.out);
    static final int mod = 1000000007;

    public static void main(String[] args) {

        solve();
        out.close();

    }

    static void solve() {
        int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        }

    }
} public class Main {
    static class FS {
        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());
        }

        double nextDouble() {
            return Double.parseDouble(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 long[] readLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    }

    static final FS sc = new FS();
    static final PrintWriter out = new PrintWriter(System.out);
    static final int mod = 1000000007;

    public static void main(String[] args) {

        solve();
        out.close();

    }

    static void solve() {
        int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        }

    }
} Main


import java.util.*;
import java.io.*;

public class Main {
    static class FS {
        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());
        }

        double nextDouble() {
            return Double.parseDouble(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 long[] readLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    }

    static final FS sc = new FS();
    static final PrintWriter out = new PrintWriter(System.out);
    static final int mod = 1000000007;

    public static void main(String[] args) {

        solve();
        out.close();

    }

    static void solve() {
        int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (n % a == 0) {
            out.println((n / a) * b);
        } else {
            out.println(((n / a) * b) + b );
        }

    }
}


