def merge_dictionaries_three(dict1,dict2, dict3):
    import collections as ct
    
    merged_dict = dict(ct.ChainMap({},dict1,dict2,dict3))
    return merged_dict
def heap_queue_largest(nums,n):
  import heapq as hq
  
  largest_nums = hq.nlargest(n, nums)
  return largest_nums