B'The cuteness of a binary string is the number of texttt{1} s divided by the length of the string. For example, the cuteness of texttt{01101} is frac{3}{5} . Juju has a binary string s of length n . She wants to choose some non-intersecting subsegments of s such that their concatenation has length m and it has the same cuteness as the string s . More specifically, she wants to find two arrays l and r of equal length k such that 1 <= q l_1 <= q r_1 < l_2 <= q r_2 < ldots < l_k <= q r_k <= q n , and also: Juju does not like splitting the string into many parts, so she also wants to minimize the value of k . Find the minimum value of k such that there exist l and r that satisfy the constraints above or determine that it is impossible to find such l and r for any k . The first line contains a single integer t ( 1 <= q t <= q 10^4 ) -- the number of test cases. The first line of each test case contains two integers n and m ( 1 <= q m <= q n <= q 2 cdot 10^5 ). The second line of each test case contains a binary string s of length n . It is guaranteed that the sum of n over all test cases does not exceed 2 cdot 10^5 . For each test case, if there is no valid pair of l and r , print -1 . Otherwise, print k + 1 lines. In the first line, print a number k ( 1 <= q k <= q m ) -- the minimum number of subsegments required. Then print k lines, the i -th should contain l_i and r_i ( 1 <= q l_i <= q r_i <= q n ) -- the range of the i -th subsegment. Note that you should output the subsegments such that the inequality l_1 <= q r_1 < l_2 <= q r_2 < ldots < l_k <= q r_k is true. In the first example, the cuteness of texttt{0011} is the same as the cuteness of texttt{01} . In the second example, the cuteness of texttt{11000011'...