Gemstone Tracker

You are given a series of commands to simulate a gemstone tracking system. Implement the class GemstoneTracker which supports the following operations:

• Discover: Mark a gemstone as discovered. If the gemstone was previously misplaced, its state is restored.
• Misplace: Mark a gemstone as misplaced (i.e., remove it from the discovered set if present).
• Count: Return the current number of gemstones in the discovered set.

You are also required to process a sequence of commands. Each command is given as a string in one of the following formats:

• D <gemstone_id>: Discover the gemstone with the given ID.
• M <gemstone_id>: Misplace the gemstone with the given ID.
• C: Output the current count of discovered gemstones.

Your program should process these commands in order and print the results of each count operation.

Note: When a gemstone is rediscovered after being misplaced, it is added back to the discovered set.

inputFormat

The input is read from standard input (stdin) and is formatted as follows:

1. The first line contains an integer n representing the total number of commands.
2. The next n lines each contain a command. A command is one of the following formats:
   • D <gemstone_id> (to discover a gemstone)
   • M <gemstone_id> (to misplace a gemstone)
   • C (to output the current count)

outputFormat

Whenever a command C is encountered, output the current count of discovered gemstones on a new line to standard output (stdout).

## sample

6
D ruby01
D emerald02
C
M ruby01
C
D ruby01

2
1

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