#include <string>
#include <list>

class bad_thing: public std::exception{
  const char* msg;
  virtual const char* what() const throw() {
    return msg;
  }
public:
  bad_thing(const char* _msg)
  : msg(_msg) {}
};

// Function to find the maximum element of a list.
// The list may contain one or more elements.
// We throw an exception if there are zero elements.
//
template <class Tp>
Tp max(const std::list<Tp>& arg) {
  using namespace std;
  if (!arg.size()) throw bad_thing("max of empty list");
  typename list<Tp>::const_iterator ii(arg.begin());
// Initialize the result to the first element.
// This is well known to be the only valid way of doing it:
  Tp rslt(*ii++);
  while(ii != arg.end()) {
    rslt = max(rslt, *ii++);
  }
  return rslt;
}