#include <fstream>
#include <cstdio>

using namespace std;
ofstream fout("fact.out");
int p,n;
int main()
{
    freopen("fact.in","r",stdin);
    scanf("%d",&p);
    if(p!=0 && p!=5)
        n=((p/6)*25+(p%6)*5);
    else{
        if(p==0)
            n=1;
        if(p==5)
            n=-1;
    }
    fout<<n<<'\n';
    return 0;
}