def sqrt(n):
    lo, hi = 0, n + 1
    while hi - lo > 1:
        m = (hi + lo) // 2
        if m * m <= n:  lo = m
        else:           hi = m
    return lo

n = int(input())
s = input()
if s.count('Q') < n:
    print(-1)
else:
    sq = sqrt(n)
    if sq * sq == n:
        print('Q' * sq)
    else:
        print(-1)