问题 A: Almost Correct

• Array x and y are of equal length, and the length should not exceed 120.

• 1≤xi<yi≤n for all 1≤i≤m, where $m$ is the length of the two arrays.

• Algorithm SORT(x,y) can sort all 01-sequences of length n correctly except for the given one. Here algorithm SORT(x,y) takes as input a 01-sequence a of length n, and is described as follows:

• Iterate over all integers from 1 to m. For each integer i during the iteration, swap axi and ayi if axi>ayi.

The input contains multiple test cases.
The first line of the input contains an integer T (1≤T≤10^4), the number of test cases.
For each test case, the first line contains an integer n (2≤n≤16).
The next line contains $s$, the 01-sequence of length n. It is guaranteed that $s$ is not sorted, i.e., there exists some integers 1≤i<j≤n such that si=1 and sj=0.

For each test case, output m (0≤m≤120) in the first line, indicating the length of array x and y.
In the $i$-th of the next $m$ lines, print xi and yi (1≤xi<yi≤n) separated by a space.

2
2
10
3
110

0
2
1 2
2 3