2. (15 points) The following C++ program has a function called mystery #include 10 using namespace std: int mystery (int x, int & y, int z) int mainOt int x(3), y(3), z(4): int a(9), b(6), c(5): int ans: ans mystery (x y, z) ans. mystery (x-a, b, z c); , return 0: int mystery (int x, int & y, int z) if (x z) t y' = x + 3; else ( +ty: return (x + y + z)/2: L9 What is the exact output of the program? NO need to justify your