Definition: You are provided with an arithmetic question. Your task is to compute the solution using the given arithmetic operations. The only arithmetic operators needed to answer the questions are'+'(addition) and'-'(subtraction). The answer should be correct to one decimal place.
Input: Alyssa has 37 blue balloons, Sandy has 28 blue balloons, and Sallyhas 39 blue balloons. How many blue balloons do they have in all?

104.0