
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
Dianna's teacher gave her the task to substitute numbers for $a$, $b$, $c$, $d$, $e$, and $f$ in the expression $a-(b-(c-(d+(e-f))))$ and compute the result. Dianna misinterpreted the parentheses but performed the addition and subtraction accurately, coincidentally arriving at the correct result. Dianna used the numbers $1$, $2$, $3$, $4$, and $5$ respectively for $a$, $b$, $c$, $d$, and $e$. Find the number that Dianna substituted for $f$.

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