#include <fstream>
#include <iostream>
using namespace std;
ifstream f("in.txt");
ofstream g("out.txt");
int n, i, nr,j,OK;
int main()
{
    f >> n; i = 1;
    while (OK==0)
    {
        j = i;
        while (j % 5 == 0 && j != 0)
        {
            nr++;
            j /= 5;
        }
        if (nr >= n)
        {
            OK = 1;
        }
        else
            i++;
    }
    g << i;
}