Write a program that inputs 3 integers into array `a`, then 3 integers into array `b`. Each array is already sorted in ascending order. Merge them into a single array of 6 values that is also in ascending order, **without sorting the combined array**: repeatedly compare the next unused value of each array and copy the smaller one across. Output the merged array, one value per line. For example, `a` = 1, 4, 7 and `b` = 2, 3, 9 produce 1, 2, 3, 4, 7, 9.