static void Main(string[] args)
{
// read for m and k
var MAndK = Console.ReadLine();
//var MAndK = "5 120";
var MKArray = MAndK.Split(' ');
var numberOfSlots = int.Parse(MKArray[0]);
var minutes = int.Parse(MKArray[1]);
var slots = new Interval[numberOfSlots];
for (int i = 0; i < numberOfSlots; i++)
{
var slotInput = Console.ReadLine();
var slotArray = slotInput.Split(' ');
var timeSlot = new Interval();
timeSlot.Start =int.Parse(slotArray[0].Trim())*60 + int.Parse(slotArray[1].Trim());
timeSlot.End = int.Parse(slotArray[2].Trim())* 60 + int.Parse(slotArray[3].Trim());
slots[i] = timeSlot;
}
// merge intervals
var mergedSlots = Merge(slots);
//scan for free slot that has value bigger than minutes
var freeSlots = new List<Interval>();
if (mergedSlots[0].Start> minutes)
{
// add the first free slot
freeSlots.Add(new Interval
{
Start = 0,
End = mergedSlots[0].Start
});
}
for (int i = 1; i < mergedSlots.Count() ; i++)
{
if ((mergedSlots[i].Start - mergedSlots[i-1].End>=minutes))
{
freeSlots.Add(new Interval
{
Start = mergedSlots[i - 1].End,
End = mergedSlots[i].Start
});
}
}
// check the last
if ((24*60 - mergedSlots.Last().End) > minutes)
{
freeSlots.Add(new Interval
{
Start = mergedSlots.Last().End,
End = 0
});
}
// print out free slots
foreach (var freeslot in freeSlots)
{
Console.WriteLine("{0} {1} {2} {3}"
, (100 + freeslot.Start/60).ToString().Substring(1, 2)
, (100 + freeslot.Start%60).ToString().Substring(1, 2)
, (100 + freeslot.End/60).ToString().Substring(1, 2)
, (100 + freeslot.End % 60).ToString().Substring(1, 2)
);
}
}
private static List<Interval> Merge(Interval[] intervals)
{
List<Interval> merged = new List<Interval>();
var sorted = intervals.OrderBy(interval => interval.Start).ToArray();
for (int i=0; i< sorted.Length-1; i++)
{
if (sorted[i].End >= sorted[i + 1].Start)
{
// merge to make i +1 item the merged one
sorted[i + 1].Start = sorted[i].Start;
// need to check end too
if (sorted[i].End > sorted[i + 1].End)
{
sorted[i + 1].End = sorted[i].End;
}
}
else
{
merged.Add(sorted[i]);
}
}
// add last
merged.Add(sorted[sorted.Length - 1]);
return merged;
}