#include <iostream>
#include <fstream>
using namespace std;
long long int p,r,d;
int main()
{
    ifstream ka("fact.in");
    ofstream ki("fact.out");
    ka>>p;
    if(p>=0)
    {
        if(p==0)
        ki<<"1";
        if((1<=p)and(p<=4))
        ki<<"-1";
        if(p>=5)
    {
       d=5;
       while(r<p)
       {
           r++;
           d=d+5;
       }
    ki<<r;
    }
    }
    else
    ki<<"-1";
}