ch14.py

from collections import Counter

c=Counter({'a':1,'b':2,'c':-5,'d':3})

#It will return list of elements from most common to least common
l=c.most_common()
print (l)#Output:[('d', 3), ('b', 2), ('a', 1), ('c', -5)]

#Most common element can be found by accessing first index l[0]
print (l[0])#Output:('d', 3)

#Least common element can be found by accessing last index l[-1]
print (l[-1])#Output:('c', -5)