
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 $\overrightarrow{b}=(2,s)$, $\overrightarrow{c}=(1,-1)$, $\overrightarrow{m}=(s,1)$, if $\overrightarrow{b}//\overrightarrow{c}$, then the cosine value of the angle between $\overrightarrow{m}$ and $\overrightarrow{c}$ is _____.

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