
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
In tetrahedron $OABC$, a point $M$ in space satisfies $\overrightarrow{OM}=\frac{1}{2}\overrightarrow{OA}+\frac{1}{6}\overrightarrow{OB}+λ\overrightarrow{OC}$. If $\overrightarrow{MA}$, $\overrightarrow{MB}$, and $\overrightarrow{MC}$ are coplanar, then $\lambda =\_\_\_\_\_\_$.

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