
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
You are allowed to perform one of the following operations on the number written on the board:
1) If there is a digit in the original number that is not 9 and has two neighboring digits greater than 0, you can increase this digit by 1 and decrease the neighboring digits by 1.
2) Subtract 1 from any non-zero digit, except the last one, and add 3 to the next digit.
3) Decrease any sufficiently large digit by 7.

If, as a result of any of these operations, there are zeros at one or several of the leading positions, they are automatically discarded.

Initially, the number written on the board consisted of one hundred eights. What single-digit number remains in the end?

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