Each Sunday Mrs. Mahtaj who is an old woman goes to David Church and after the Sunday pray she comes back home. The traffic center has a complicated rule for closing crossroads that Mrs. Mahtaj can't understand. She is a forgetful woman who can only memorize the path from her house to church. The streets of her city are vertical or horizontal, the same as a grid with the squares of the same size. So she memorizes a path by a string of F (Forward), B (Backward), L (Left) and R (Right). For example, if there is no closed crossroad and Mahtaj is in crossroad (1,0) and faces east, if the string is BRFRLFL she reaches the crossroad (0,4). His son, Khashayar, decides to help her finding a path that can be used both for going from their house to the church and for coming back from the church to their house and does not pass any closed crossroad. I.e. Mahtaj should be able to go from her house to the church and from the church to her house by just one string. Help Khashayar to find such a path. When Mrs. Mahtaj starts the path from her house, she faces east and when she starts from the church she faces west.