T = int(input())

def rle(S):
    ret = []
    now = None
    count = 0
    for i in S:
        if(now == i):
            count += 1
        else:
            if(count > 0):ret.append((now,count))
            now = i
            count = 1
    ret.append((now,count))
    return ret

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

    rl = [(a,b) for a,b in rle(S) if a != "-"]
    P = len([a for a,b in rl if a == "P"])
    K = len([a for a,b in rl if a == "K"])
    print("K" if K >= P else "P")