1287A.py

# Name: Angry Students
# Link: https://codeforces.com/problemset/problem/1287/A
# Method: Linear scan, see last "A"ngry one
# Time: O(n)
# Space: O(1)
# Difficulty: A


if __name__ == "__main__":
    tests = int(input())

    for _ in range(tests):
        cn = int(input())
        s_arr = input()
        prev_anv = -1
        max_dist = 0
        for i, indiv in enumerate(s_arr):
            if indiv == "A":
                if prev_anv != -1:
                    max_dist = max(max_dist, i - prev_anv - 1)
                prev_anv = max(prev_anv, i)

        # At least one angry
        if prev_anv != -1:
            max_dist = max(max_dist, cn - prev_anv - 1)
        print(max_dist)