T = int(input())
for _ in range(T):
    N = int(input())
    S = list(input())

    now = S[0]
    cnt = 1
    dat = []
    for i in range(1, N):
        if S[i] != now:
            dat.append([now, cnt])
            cnt = 1
            now = S[i]
        else:
            cnt += 1
    dat.append([now, cnt])
    # print(dat)

    cntp, cntk = 0, 0
    for c, _ in dat:
        if c == 'P':
            cntp += 1
        if c == 'K':
            cntk += 1
    
    print("K" if cntp <= cntk else "P")