HI community I needed help in this coding problem.Any help would be appreciated, Thanks.

Each player has some scores based on two parameters, Coordination and Problem Solving skills. The overall skill of a team is evaluated as the sum of Problem Solving Skills of both players and the absolute difference between Coordination of both players. For example c[1] and ps 1] are Coordination and Problem Solving skills of player 1 c[2] and ps[2] are Coordination and Problem Solving Skills of Player 2 Then overall skill of the team of these two players is ps[1] + ps[2] + abs(c[1] – c[2]) The host of the contest has decided parameter K such that no team must have the absolute difference between the Coordination of both players more than K, that is, abs(c[1] — c[2]) SK It is guaranteed that there exists at least one pair of players that satisfy the constraint abs(c[1] — c[2]) Your task is to determine the maximum possible overall skill of a team that you can send in this tournament Input format an integer I denoting the number of test cases.​ N,K denoting no of players and the parameter. Next N lines contains c[i] and p[i] denoting the coordination and problem solving skill of ith player.

Constraints N 10^5 k 10^8 c[i] ,p[i] 10^8 SAMPLE INPUT 4 1 5 3 6 0 9 10 10 -10

OUTPUT 4