You are given a description of a robot's path. The robot begins at point $(0,0)$ and performs $n$ commands. Each command moves the robot some distance up, down, left or right.
The robot will stop when it has performed all commands, or immediately when it returns to a point that it has already visited. Your task is to calculate the total distance the robot moves.
The first line has an integer $n$ : the number of commands.
After that, there are $n$ lines describing the commands. Each line has a character $d$ and an integer $x$ : the robot moves the distance $x$ to the direction $d$ . Each direction is U (up), D (down), L (left), or R (right).
Print the total distance the robot moves.