import heapq
class Solution:
    def minMeetingRooms(self, intervals: List[List[int]]) -> int:
        heap = []
        heapq.heapify(heap)
        intervals = sorted(intervals, key=lambda x: x[0])
        count = 0
        for i, pair in enumerate(intervals):
            if not heap:
                count += 1
            else:
                if pair[0] < heap[0]:
                    count += 1
                else:
                    heapq.heappop(heap)
            heapq.heappush(heap, pair[1])
        return count