N = int(input())
S = input()
if "H" in S:
  print(-1)
  exit(0)
Q = S.count("Q")
if Q == 1:
  print(S)
  exit(0)
qsqrt = 0
for x in range(1, N):
  if x ** 2 == Q:
    qsqrt = x
    break
else:
  print(-1)
  exit(0)

table = [0] * (N + 1)
table[0] = -1
i, j = 0, 1
while j < len(S):
  matched = S[i] == S[j]
  if not matched and i > 0:
    i = table[i]
  else:
    if matched:
      i += 1
    j += 1
    table[j] = i

length = N - table[N]
substring = S[: length]

substringQ = substring.count("Q")
if qsqrt % substringQ:
  print(-1)
  exit(0)

print(substring * (qsqrt // substringQ))