# Perfect.

For positive integers $$a$$ and $$b$$, it is given that both $$21ab^{2}$$ and $$15ab$$ are perfect squares. Find $$min(a+b)$$

Details
A perfect square is square of an integer.

Note- I take no credit for this question. This has appeared in $$IMC , RMTC$$ and many other contests too.

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