CF10C Digital Root

Not long ago Billy came across such a problem, where there were given three natural numbers $ A $ , $ B $ and $ C $ from the range $ [1,N] $ , and it was asked to check whether the equation $ AB=C $ is correct. Recently Billy studied the concept of a digital root of a number. We should remind you that a digital root $ d(x) $ of the number $ x $ is the sum $ s(x) $ of all the digits of this number, if $ s(x)

N/A

N/A

For the first sample the required triples are $ (3,4,3) $ and $ (4,3,3) $ .