#include <fstream>
#define LIM 30

using namespace std;

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

int p;

int nrzero(int nr) {
    int s = 0;

    while (nr >= 5) {
        s += nr / 5;
        nr /= 5;
    }
    return s;
}

int cautbin() {
    int pas = 1 << LIM, r = 0;

    while (pas != 0) {
        if (nrzero(r + pas) < p) {
            r += pas;
        }
        pas >>= 1;
    }

    return r + 1;
}

int main()
{
    in >> p;
    //out << nrzero(1220703125) << '\n';
    if (nrzero(cautbin()) == p) {
        out << cautbin();
    }
    else {
        out << -1;
    }
    return 0;
}