The first line of the input contains an integer $T(1\leq T\leq10)$, denoting the number of test cases.
In each test case, there are $2$ integers $n,m(2\leq n\leq 100000,1\leq m\leq 100000)$ in the first line, denoting the length of $S$ and the number of queries.
In the next line, there is a string $S$ consists of $n$ lower-case English letters.
Then in the following $m$ lines, there are $2$ integers $l_i,r_i(1\leq l_i<r_i\leq n)$ in each line, denoting a query.