Bob is learning about lines in his math class.

As a truly gifted kid, Bob always liked to ask questions. Naturally, he raised his hand and asked:

Can a line be perpendicular to itself?

The other students burst into laughter. Bob sunk deep into his seat, trying to hide himself.

After the buzz died down, Alice, the teacher, continued to stand tall with a bright smile on her face.

Good question, Bob. Indeed, a line can be perpendicular to itself!

However, the real question is: Can you provide an example?

Bob stood up and walked to the chalkboard, determined to find the answer.

Input Specification

There is no input.

Output Specification

Output one line containing the slope of any line which is perpendicular to itself.