#include<iostream>
#include<fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");

int main()
{
    int p,i,nr;
    in>>p;
    if(p==0)out<<"1";
    else
    if(p%6==5)out<<"-1";
    else{i=0;nr=0;
    while(i<p)
    {
        i=i+1;
        if(i%6!=5)nr=nr+5;

    }

    out<<nr;
    }
    return 0;
}