Robot Return to the Origin

This problem challenges you to determine whether a robot that follows a sequence of movement commands returns to its original position at the origin (0, 0). The commands are given as a string where each character represents a unit move in one of the four cardinal directions: L (left), R (right), U (up), and D (down).

The robot starts at (0, 0) and moves one unit per command. After executing all the commands, if the robot is back at the origin, output YES; otherwise, output NO.

The movement can be mathematically expressed using the coordinate system. Let the initial position be \((0,0)\). Each command modifies the position as follows:

• L: \(x = x - 1\)
• R: \(x = x + 1\)
• U: \(y = y + 1\)
• D: \(y = y - 1\)

The goal is to check if \(x=0\) and \(y=0\) after processing the entire string of commands.

inputFormat

The input consists of a single line containing a string of characters. Each character is one of L, R, U, or D, representing a movement command.

outputFormat

Output a single line with the word YES if the robot returns to the origin after executing all commands, otherwise output NO.

UDLR

YES