Which of the following numbers is a irrational number: -200, -1.5, -1, 0, 1, 1.5, 200, pi, e, sqrt(-1)?
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### Instruction:
Which of the following numbers is a irrational number: -200, -1.5, -1, 0, 1, 1.5, 200, pi, e, sqrt(-1)?

### Response:

Square root of -1 is an irrational number