Xiao Ming likes those N candies he collects very much. There are two kinds of candies, A
and B. One day, Xiao Ming puts his candies in a row and plays games. And he can replace the
Lth candy to the Rth candy with the same kind of candies. Now, he wonder that if he eats the
Lth candy to Rth candy, he can eat how many B candy continuously at most. For each Xiao
Ming’s query, give the number of the B candy he can eat continuously at most.

In the first line, there is an integer T, indicates the number of test cases.
For each case, there are two integers N and M in the first line, indicate the number of
candies and the time of Xiao Ming’s operations.
The second line is a N-length string consist of character A and B, indicates the row of
candies Xiao Ming put.
The next M line is Xiao Ming’s operations. There are two kind of operations:
1. 1 L R v, indicate Xiao Ming replaces the Lth candy to the Rth candy with A candies
(v==1) or B candies ( v == 2 ).
2. 2 L R, indicate Xiao Ming wonder that there are how many continuous B candies
between the Lth candy to the Rth candy most.

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