#1107. 「USACO 2013 Open Silver」Luxury River Cruise

* Line 1: Three space-separated integers N, M, and K.

* Lines 2..N+1: Line i+1 has two space-separated integers,

representing the number of the ports that port i's left and right rivers lead to, respectively.

* Line N+2: M space-separated characters, either 'L' or 'R'. 'L' represents a choice of 'left' and 'R' represents a choice of 'right'.

* Line 1: A single integer giving the number of the port where Bessie's cruise ends.

输入 #1

4 3 3 
2 4 
3 1 
4 2 
1 3 
L L R

输出 #1

4

The port numbers are arranged clockwise in a circle, with 'L' being a clockwise rotation and 'R' being a counterclockwise rotation. The sequence taken is LLRLLRLLR.

After the first iteration of the sequence of directions, Bessie is at port 2 (1 -> 2 -> 3 -> 2); after the second, she is at port 3 (2 -> 3 -> 4 -> 3), and at the end she is at port 4 (3 -> 4 -> 1 -> 4).