#include <string>
#include <iostream>
#include <iomanip>

class Activity
{
public:
  Activity(int start, int stop, std::string const& descr)
    : mstart(start), mstop(stop), mdescr(descr) {}
  Activity(std::istream& in) : mstart(0), mstop(0), mdescr("")
  {
    int h, m;
    char colon, minus;
    
    in >> h >> colon >> m;
    mstart = h*60 + m;

    in >> minus;
    
    in >> h >> colon >> m;
    mstop = h*60 + m;

    in >> std::ws;
    getline(in, mdescr);
  }

  bool operator<(Activity const& rhs) const
  {
    return mstop < rhs.mstart;
  }
  
  int timeTo(Activity const& rhs) const
  {
    return rhs.mstart - mstop;
  }

  friend std::ostream& operator<<(std::ostream& os, Activity const& a)
  {
    return os << a.mstart/60 << ':' << std::setfill('0')
              << std::setw(2) << a.mstart%60 << " - "
              << a.mstop/60 << ':' << std::setfill('0')
              << std::setw(2) << a.mstop%60 << "  "
              << std::setfill(' ') << a.mdescr;
  }
  
private:
  int mstart;
  int mstop;
  std::string mdescr;
};

#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <algorithm>

using namespace std;

int main(int argc, char* argv[])
{
  vector<Activity> schedule;

  if ( argc != 2 )
  {
    cerr << "ERROR: no file given on command line" << endl;
    return 1;
  }

  ifstream ifs(argv[1]);
  
  if ( ! ifs )
  {
    cerr << "ERROR: '" << argv[1] << "' could not be opened" << endl;
    return 2;
  }

//  schedule.emplace_back(8*60, 8*60, "Workday start");
  
  string line;
  while (getline(ifs, line))
  {
    istringstream iss(line);
    schedule.emplace_back(iss);
  }
  ifs.close();

//  schedule.emplace_back(18*60, 18*60, "Workday end");

  sort(schedule.begin(), schedule.end());

  for (Activity& a : schedule)
    cout << a << endl;
  
  int max = 0;
  int max_index = -1;
  for (unsigned int i = 1; i < schedule.size(); ++i)
  {
    if (schedule.at(i-1).timeTo(schedule.at(i)) > max)
    {
      max = schedule.at(i-1).timeTo(schedule.at(i));
      max_index = i;
    }
  }
  
  if (max_index != -1)
  {
    cout << "Largest consecutive block of unbooked time is between: " << endl
         << schedule.at(max_index-1) << endl
         << schedule.at(max_index) << endl;
  }
  else
  {
    cout << "No unbooked time found." << endl;
  }

  return 0;
}