
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
Given the universal set $U=\{-1, 2, 3, a\}$, and set $M=\{-1, 3\}$. If the complement of $M$ in $U$ is $\complement_U M=\{2, 5\}$, then the value of the real number $a$ is _____.

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