human
Solve in Python:
Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the original place. 


The move sequence is represented by a string. And each move is represent by a character. The valid robot moves are R (Right), L (Left), U (Up) and D (down). The output should be true or false representing whether the robot makes a circle.

Example 1:

Input: "UD"
Output: true


Example 2:

Input: "LL"
Output: false
assistant
#Here is the Python program you requested.

class Solution:
     def judgeCircle(self, moves):
         """
         :type moves: str
         :rtype: bool
         """
         if not moves:
             return True
         if len(moves) % 2 == 1:
             return False
         
         up, left = 0, 0
         for move in moves:
             if move == 'U':
                 up += 1
             if move == 'D':
                 up -= 1
             if move == 'L':
                 left += 1
             if move == 'R':
                 left -= 1
         return up == 0 and left == 0