T = int(input())
for _ in range(T):
    N = int(input())
    S = input().rstrip()
    D = []
    k = S[0]
    cnt = 1
    for i in range(1, len(S)):
        if S[i] == k:
            cnt += 1
        else:
            D.append((k, cnt))
            k = S[i]
            cnt = 1
    D.append((k, cnt))
    K, P = 0, 0
    for k, cnt in D:
        if k == "K":
            K += 1
        elif k == "P":
            P += 1
    print("K" if K >= P else "P")