You have a sentence in the string format in the input. Count all the POS tags. The output should be a Python dictionary with a POS tag as a key and several occurrences as a value. For example, if you have a sentence with two NN tags, then you'll get {'NN': 2} in the output.
Don't forget to tokenize the input sentence.
NLTK tagsets usually contain tuples. You can unpack a tuple with for (word, pos) in tagged
You may create a list of all POS tags in a sentence and then go through each of them. A for loop can help you.
You can count POS tags in the following way: ['NN', 'VBZ', 'ADJ', 'NN'].count('NN'). The output will be: 2. Another way to count the POS tags is to create a list of words of a specific POS and then count it with len().