#include <iostream>
#include<fstream>

using namespace std;

int main()
{
    fstream in, out;
    long n, p, nr0, ci, i;
    in.open("fact.in", ios::in);
    out.open("fact.out", ios::out);
    in>>p;
    nr0=0;
    i=2;
    while(nr0!=p)
    {
        i++;
        if(i%10==5)
        {
            ci=i;
            while(ci%10==5)
            {


                nr0++;
                ci=ci/5;
            }
        }
        if(i%10==0)
        {
            ci=i;
            while(ci%10==0)
            {
                nr0++;
                ci=ci/10;
            }
        }
    }
    out<<i;
}