Browser History Simulator

This problem simulates a simplified web browser history management system. You are given a sequence of operations that manipulate the browser history. Initially, the browser starts at its homepage, which is homepage. The operations are in one of the following forms:

• visit <url>: Visit a new URL. This clears any forward history.
• back <steps>: Go back by a given number of steps. You cannot go back beyond the homepage.
• current: Output the current URL that the browser is showing.

Your task is to simulate these operations. Let $n$ be the number of operations. For each current operation, output the current URL. All formulas are written in LaTeX format; for example, the number of operations is given by $n$.

inputFormat

The input is read from stdin and has the following format:

1. An integer n representing the number of operations.
2. n lines each containing one operation. Each operation is one of:
   • visit <url>
   • back <steps>
   • current

outputFormat

For each current operation encountered, output the current URL on a new line on stdout.

## sample

5
visit google.com
visit youtube.com
back 1
current
current

google.com
google.com

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