
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
The "Fibonacci" sequence was discovered by the 13th-century Italian mathematician Fibonacci. A series of numbers in this sequence are often referred to as magical numbers. The specific sequence is: $1$, $1$, $2$, $3$, $5$, $8…$, that is, starting from the third term of the sequence, each number is the sum of the two preceding numbers. Given that the sequence $\{a_n\}$ is the "Fibonacci" sequence, and $S_n$ is the sum of the first $n$ terms of the sequence $\{a_n\}$, then  
(Ⅰ) $S_7=$ _______;  
(Ⅱ) If $a_{2017}=m$, then $S_{2015}=$ _______ (Express in terms of $m$).

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