Transaction: Rollback Handling on Exception

In this problem, you will create a program that implements a TransactionManager class to execute multiple operations as a single transaction, rolls back the value to 0 if a failure operation occurs, and displays the result to standard output.

Learning Objective: Understand how to rollback transactions on exception to maintain consistency

Input

Line 1: Number of operations
Following: Each operation ("add [value]" or "fail")

Output

Operation log:
Executing: [operation]
On success: Committed. Final value: [value]
On failure: Rollback. Value restored: 0

Example

Input:

3
add 10
add 20
add 5

Output:

Executing: add 10
Executing: add 20
Executing: add 5
Committed. Final value: 35