import sys
input = sys.stdin.readline

T=int(input())
for tests in range(T):
    N=int(input())
    S=input().strip()

    LIST=[]
    now=[]
    for s in S:
        if s=="-":
            if now!=[]:
                LIST.append(now)
            now=[]
        else:
            now+=[s]

    P=0
    K=0

    for l in LIST:
        if l[0]==l[-1]=="P":
            P+=1
        elif l[0]==l[-1]=="K":
            K+=1

    if K>=P:
        print("K")
    else:
        print("P")