#include <iostream>
#include <fstream>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int p,i=5,s,a;
int main()
{
    f>>p;
    while (s<p)
    {
        a=i;
        if (a%5==0) {while (a%5==0) {s++; a/=5;}}
        i+=5;
    }
    if (s==p) g<<i-5;
    else g<<"-1";
    return 0;
}