You are given a math word problem and you are supposed to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

At the beach , Janet and her sister both built sandcastles and then measured their heights . Janet 's sandcastle was 3.6666666666666665 feet tall and her sister 's was 2.3333333333333335 feet tall . How much taller was Janet 's sandcastle than her sister 's ?
1.3333333333333333