Q=int(input())
for _ in range(Q):
  N=int(input())
  S=input()
  x=0
  y=0
  used=[False]*N
  for i in range(N):
    if used[i]==True:
      continue
    if S[i]=='-':
      continue
    r=N-1
    used[i]=True
    for j in range(i+1,N):
      if S[j]=='-':
        r=j-1
        break
      used[j]=True
    if S[i]=='P' and S[r]=='P':
      y+=1
    if S[i]=='K' and S[r]=='K':
      x+=1
  if x>=y:
    print('K')
  else:
    print('P')