The keys in a dictionary are guaranteed to be unique, but the values are not. Write a function called

 count_values(mappings) 

that takes a list of mappings representing a single dictionary as an argument and, after converting the list to its corresponding dictionary, computes and returns the number of distinct values contained in the dictionary. Recall that to create a dictionary from mappings you need the code

D = {}
for mapping in mappings:
  key = mapping[0]
  value = mapping[1]
  D[key] = value

# at this spot, outside the loop above, it's as if D was the parameter

Paste this code into the space below, then solve the problem with the dictionary D.