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There are two strings A and B with equal length. Both strings are made up of lower case letters. Now you have a powerful string painter. With the help of the painter, you can change a segment of chara...

You are given an arraya1,a2,…,ana1,a2,…,an. You can perform the following operation any number of times:Choose a pair of two neighboring equal elementsai=ai+1ai=ai+1(if there is at least one such...