#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("fact.in");
ofstream fout("fact.out");

int main()
{
    int p,n,a=5,b,no=0;
    fin>>p;
    while(no<p)
    {
        b=a;
        b/=5;
        while(b%5==0)
        {
            b/=5;
            no++;
        }
        no++;
        a+=5;
    }
    if(a==0)
        fout<<"1";
    else if (p!=no) fout<<"-1";
        else fout<<a-5;
    return 0;
}