Given that , find the smallest positive integer , such that the number of digits of the two numbers and are identical.
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We can find the number of digits in a number by taking the floor of a log of a number, and adding one, as such: ⌊ l o g x ⌋ + 1 = number of digits in x . Therefore, we have the number of digits in 5 x = ⌊ x l o g 5 ⌋ + 1 , because of the property l o g x y z = z l o g x y . l o g 5 = l o g 1 0 − l o g 2 , because of the property l o g x − l o g y = l o g y x , and from there it is just brute force by calculating out each scenario for x > 5 0 .