Answer:
def main ():
sentence = input("Please enter a sentence:")
print("Original Sentence:",sentence)
# start at the third character
for i in range(2, len(sentence), 3):
# access the string by index
print("Every third letter:", sentence[i])
Step-by-step explanation:
def helps define the sentence ( input)
in order to start printing from third letter we start the range from 2 and keep the step 3 . The range i is in square parenthesis to show the range and access string.