def run_length_encoding(A):
  B = []
  for a in A:
    if B and B[-1][0] == a:
      B[-1][1] += 1
    else:
      B.append([a, 1])
  return B

for _ in range(T := int(input())):
  N = int(input())
  S = input()
  
  T = run_length_encoding(S)
  K = P = 0
  for c, l in T:
    if c == 'K': K += 1
    elif c == 'P': P += 1
  
  print('K' if K >= P else 'P')