package com.company;

import java.io.*;

public class Main {

    public static int count5(int n) {
        int nr = 0, c5 = 0;
        while (n % 5 == 0) {
            c5++;
            n /= 5;
        }
        return c5;
    }

    public static void main(String[] args) {
        String filename= "factorial.in";
        String line=null;
        FileReader fr= null;
        try {
            fr = new FileReader(filename);
            BufferedReader bufferedReader = new BufferedReader(fr);

            line = bufferedReader.readLine();
            int nr=Integer.parseInt(line);

            int n = 0;
            int i = 1, c5 = 0;
            do {
                if (i % 5 == 0)
                    c5 = c5 + Main.count5(i);
                i++;
            }
            while (c5 < nr);
            i -= 1;

            FileWriter fw=new FileWriter("factorial.out");
            BufferedWriter br=new BufferedWriter(fw);
            br.write(Integer.toString(i));
            br.close();
            fr.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}