
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
Among the following propositions:

1. The converse of "The areas of congruent triangles are equal";
2. The negation of "If $ab=0$, then $a=0$";
3. The contrapositive of "The three interior angles of an equilateral triangle are all $60^{\circ}$".

The numbers of the true propositions are __________ (Fill in all the numbers of the true propositions in the blank).

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