⭐IN THE GIVEN PROBLEM , WE NEED TO FIND THE LARGEST PAIR SUM
⭐FOR THIS FIRST WE SORT THE ARRAY, AFTER SORTING , WE FIND THE 1ST LARGEST ELEMENT IN THE ARRAY.
⭐AFTER THAT WE NEED TO FIND THE SECOND LARGEST ELEMENT.
⭐THAN TAKE A LARGEST PAIR SUM.