import collections
c = collections.Counter([3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5])
print('c = {}'.format(c))
num_of_five = c[5]
print('num_of_five = {}'.format(num_of_five))
c[3] += 57
print('c = {}'.format(c))