#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int fact(int n)
{
    int c=5*n,cnt=0;
    if (n%5==0) return -1;
    while (n !=cnt)
    {
        cnt =0;
        for (int i=5; c/i>=1; i *= 5)
            cnt += c/i;
        if (cnt == n) return c;
        if (cnt < n) c+=5;
        else c-=5;

    }
    return c;
}
int main()
{
    int n;
    in >> n;
    if (n==0) out << "1";
    else out << fact(n);
    return 0;
}