
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 that the function \( f(x) \) is a decreasing function on \( \mathbf{R} \) and is an odd function. If \( m \) and \( n \) satisfy the system of inequalities \(\left\{\begin{array}{l}f(m)+f(n-2) \leqslant 0, \\ f(m-n-1) \leqslant 0,\end{array}\right.\) then the range of \( 5m-n \) is \(\qquad\).

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