Book Stack Operations

You are given a series of operations to perform on a stack of book IDs. The stack supports the following operations:

• push x: Push the book with ID x onto the stack.
• pop: Remove the book from the top of the stack.
• max: Print the maximum book ID present in the stack at that moment.

It is guaranteed that pop and max operations will only be called when the stack is non-empty.

Your task is to implement these operations efficiently. For each max operation, output the current maximum value in the stack on a new line.

inputFormat

The input consists of an integer N on the first line, representing the total number of operations. Each of the following N lines contains a single operation in one of the following formats:

• push x where x is an integer.
• pop
• max

All inputs are read from stdin.

outputFormat

For each max operation, output the maximum book ID currently in the stack. Each result should be printed on a separate line to stdout.

## sample

6
push 1
push 2
max
push 3
pop
max

2
2

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