#include <fstream>

using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int main()
{
    int p, nrz, x, y;
    fin>>p;
    nrz=0;
    x=5;
    while(nrz<p)
    {
        y=x;
        while(y%5==0)
        {
            nrz++;
            y=y/5;
        }
        x=x+5;
    }
    if(nrz>p)
        fout<<"-1";
    else
        fout<<x-5;
}