import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
} import java.io.*; io.* java public class Main {
    public static void main(String[] args) throws Exception {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
} Main public static void main(String[] args) throws Exception {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        }
    } main {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        }
    } try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        } catch(Exception e){
            System.out.println(e);
        } Exception e {
            System.out.println(e);
        } System.out.println(e) System.out.println System.out System System.out e {
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String strSplit[] = br.readLine().split(" "); strSplit br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int N = Integer.parseInt(strSplit[0]); N Integer.parseInt(strSplit[0]) Integer.parseInt Integer strSplit[0] strSplit 0 int X = Integer.parseInt(strSplit[1]); X Integer.parseInt(strSplit[1]) Integer.parseInt Integer strSplit[1] strSplit 1 int T = Integer.parseInt(strSplit[2]); T Integer.parseInt(strSplit[2]) Integer.parseInt Integer strSplit[2] strSplit 2 int count = 0; count 0 while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            } true {
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            } N = N - X N N - X N X count++ count if(N <= 0){
                    break;
                } N <= 0 N 0 {
                    break;
                } break; System.out.println(T*count) System.out.println System.out System System.out T*count T count String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
} Main
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String strSplit[] = br.readLine().split(" ");
            int N = Integer.parseInt(strSplit[0]);
            int X = Integer.parseInt(strSplit[1]);
            int T = Integer.parseInt(strSplit[2]);
            
            int count = 0;
            while(true){
                N = N - X;
                count++;
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(T*count);
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
}