B'There are n positive integers written on the blackboard. Also, a positive number k geq 2 is chosen, and none of the numbers on the blackboard are divisible by k . In one operation, you can choose any two integers x and y , erase them and write one extra number f(x + y) , where f(x) is equal to x if x is not divisible by k , otherwise f(x) = f(x / k) . In the end, there will be a single number of the blackboard. Is it possible to make the final number equal to 1 ? If so, restore any sequence of operations to do so. The first line contains two integers n and k -- the initial number of integers on the blackboard, and the chosen number ( 2 <= q n <= q 16 , 2 <= q k <= q 2000 ). The second line contains n positive integers a_1, ldots, a_n initially written on the blackboard. It is guaranteed that none of the numbers a_i is divisible by k , and the sum of all a_i does not exceed 2000 . If it is impossible to obtain 1 as the final number, print "NO" in the only line. Otherwise, print "YES" on the first line, followed by n - 1 lines describing operations. The i -th of these lines has to contain two integers x_i and y_i to be erased and replaced with f(x_i + y_i) on the i -th operation. If there are several suitable ways, output any of them. In the second sample case: '...