#include <iostream>
#include <fstream>

using namespace std;

ifstream f ("fact.in");
ofstream g ("fact.out");

int main()
{
    int p, n, i=0, j;
    f >> p;
    if (p==0)
        g << 1;
    else
    {
        while ( n < p )
        {
            i += 5;
            j = i;
            while ( j % 5 == 0)
            {
                n++;
                j /= 5;
            }
        }
        g << i;
    }
    return 0;
}