CF578B "Or" Game

You are given $ n $ numbers $ a_{1},a_{2},...,a_{n} $ . You can perform at most $ k $ operations. For each operation you can multiply one of the numbers by $ x $ . We want to make  as large as possible, where  denotes the bitwise OR. Find the maximum possible value of  after performing at most $ k $ operations optimally.

The first line contains three integers $ n $ , $ k $ and $ x $ ( $ 1

Output the maximum value of a bitwise OR of sequence elements after performing operations.

For the first sample, any possible choice of doing one operation will result the same three numbers $ 1 $ , $ 1 $ , $ 2 $ so the result is . For the second sample if we multiply $ 8 $ by $ 3 $ two times we'll get $ 72 $ . In this case the numbers will become $ 1 $ , $ 2 $ , $ 4 $ , $ 72 $ so the OR value will be $ 79 $ and is the largest possible result.