T = int(input())
*stage, = [list(map(str, input().split())) for _ in range(T)]

for s in stage:
    if '-oo' in s[1] or 'oo-' in s[1] or 'o-o' in s[1] or 'ooo' in s[1]:
        print('O')
    else:
        print('X')