B"Little Petya likes points a lot. Recently his mom has presented him n points lying on the line OX. Now Petya is wondering in how many ways he can choose three distinct points so that the distance between the two farthest of them doesn't exceed d. Note that the order of the points inside the group of three chosen points doesn't matter. The first line contains two integers: n and d (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89105; 1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89d xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89109). The next line contains n integers x1, xe2 x80 x89x2, xe2 x80 x89..., xe2 x80 x89xn, their absolute value doesn't exceed 109 -- the x-coordinates of the points that Petya has got. It is guaranteed that the coordinates of the points in the input strictly increase. Print a single integer -- the number of groups of three points, where the distance between two farthest points doesn't exceed d. Please do not use the %lld specifier to read or write 64-bit integers in xd0 xa1++. It is preferred to use the cin, cout streams or the %I64d specifier. In the first sample any group of three points meets our conditions. In the seconds sample only 2 groups of three points meet our conditions: {-3, -2, -1} and {-2, -1, 0}. In the third sample only one group does: {1, 10, 20}."...