#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>

using namespace std;

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

int N;

int digits(int N) {
    int ans = 0;
    for (N /= 5; N; N /= 5)
        ans += N;
    return ans;
}

int main()
{
    fin >> N;
    int ans = 0;
    for (int i = 29; i >= 0; --i) {
        if (digits(ans + (1 << i)) < N) {
            ans += (1 << i);
        }
    }
    if (digits(ans + 1) == N) {
        fout << ans + 1;
    }
    else {
        fout << -1;
    }

    return 0;
}