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

Context: After resting they decided to go for a swim. The depth of the water is 15 times Dean's height. Dean is 4 feet taller than Ron. If Ron stands at 13 feet 

 Question: How deep was the water?
255