n = int(input())
s = input()
x = 0
ng = False
for c in s:
    if c == 'Q':
        x += 1
    if c == 'H' or c == '9':
        ng = True
if ng:
    print(-1)
elif x>0:
    ok = True
    k = 1
    while int(pow(k,k)) < x:
        k += 1
    if int(pow(k,k)) != x or n%k != 0:
        ok = False
    m = n//k
    for i in range(k):
        if s[i*m:(i+1)*m] != s[0:m]:
            ok = False
            break
    if ok:
        print(s[0:m])
    else:
        print(-1)
else:
    print(-1)