#include <fstream>
#define ull unsigned long long
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");

ull p;

void Read()
{
    fin >> p;
    fin.close();
}


void Solve()
{
    ull nr = 0;
    ull copie;
    ull ordin;
    while(p > 0)
    {
        ordin = 0;
        nr += 5;
        copie = nr;
        while(nr % 5 == 0)
        {
            nr /= 5;
            ordin++;
        }
        p -= ordin;
        nr = copie;
    }
    if(p == 0)
        fout << copie;
    else fout << -1;
}

int main()
{
    Read();

    if(p == 0)
    {
        fout << 1;
        return 0;
    }

    Solve();

    return 0;
}