
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
A courtyard table tennis tournament involving 15 players is conducted according to specific rules. In each round, two players compete against each other. After each round, the loser receives a black card. A player who receives two black cards is eliminated from the tournament. The last remaining player is declared the champion. In table tennis, there are no ties. How many rounds were there in the tournament if the champion lost exactly once?

Present the answer in LaTex format: \boxed{Your answer}
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