CF79E Security System

Fox Ciel safely returned to her castle, but there was something wrong with the security system of the castle: sensors attached in the castle were covering her. Ciel is at point $ (1,1) $ of the castle now, and wants to move to point $ (n,n) $ , which is the position of her room. By one step, Ciel can move from point $ (x,y) $ to either $ (x+1,y) $ (rightward) or $ (x,y+1) $ (upward). In her castle, $ c^{2} $ sensors are set at points $ (a+i,b+j) $ (for every integer $ i $ and $ j $ such that: $ 0

In the first line there are five integers $ n,t,a,b,c $ ( $ 2

If Ciel's objective is possible, output in first line $ 2n-2 $ characters that represent her feasible steps, where $ i $ -th character is R if $ i $ -th step is moving rightward, or U if moving upward. If there are several solution, output lexicographically first one. Character R is lexicographically earlier than the character U. If her objective is impossible, output Impossible.

The answers for the first sample and the second sample are shown on the picture:  Here, a red point represents a point that contains a sensor.