
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 the sequence ${a_n}$ where $a_1=1$ and $$a_{n+1}= \frac {a_{n}}{2a_{n}+1}$$.
1. Let $$b_{n}= \frac {1}{a_{n}}$$, find the general term formula for the sequence ${b_n}$.
2. If $c_n=a_n \cdot a_{n+1}$, find the sum of the first $n$ terms, $S_n$, of the sequence ${c_n}$.

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