T = int(input())

for _ in range(T):
    N = int(input())
    S = input()
    k, p = 0, 0
    left = ""
    right = ""
    for i in range(N):
        if S[i] == "-":
            if i >= 1 and S[i-1] != "-":
                if left == "K" and right == "K":
                    k += 1
                elif left == "P" and right == "P":
                    p += 1
        else:
            right = S[i]
            if i == 0 or S[i-1] == "-":
                left = S[i]
    if S[-1] != "-":
        if left == "K" and right == "K":
            k += 1
        elif left == "P" and right == "P":
            p += 1
    if k >= p:
        print("K")
    else:
        print("P")