Sort Station#1457
At the sorting railway station, there are freight cars on the track, which must be arranged into a train. All cars have the same length, but each car contains a different cargo, so their weights may vary. The workers at the station must arrange the cars in non-decreasing order of their weights before the train can depart.
Usually, shunting or electric locomotives are used for this purpose, but at this station, an experimental device is being tested. It is expected that this device will significantly reduce the time needed to form trains.
This device moves above the cars on an air cushion. Its length slightly exceeds that of two cars. It can be positioned above two adjacent cars, lift them both, and swap their positions. However, the lifting capacity of the device is limited: it can only perform this operation if the combined weights of the two cars do not exceed .
Your task is to write a program to determine whether it is possible to sort the cars in the required order, using only the operations allowed by the experimental device.
The first line contains two integers (2 \le n \le 100,\!000) and (2 \le M \le 10^9) — the number of cars and the lifting capacity of the device.
The second line contains integers m_1, m_2, , m_n (1 \le m_i \le 10^9), the weights of the cars in the order they are currently on the track. The weights are pairwise distinct.
Print Yes if it is possible to sort the cars using the experimental device. Otherwise, print No.
Example 1
Example 2