Write a C++ program that reads from keyboard 3 integers, with proper input prompt, and then displays the maximum sum of any pair of numbers from these three. If the 3 numbers are 5, 6 and 7 for instance, then the maximum sum comes from 6+7=13. Draw the flowchart of this C++ program, and also desk check the program for the three input integers 12, 3 and 7, or a different set of 3 numbers which will make the desk checking less trivial within your program design.