import sys
input = sys.stdin.readline

T=int(input())
Q=[list(input().split()[1]) for i in range(T)]

for S in Q:
    N=len(S)
    flag=0

    for i in range(N-2):
        if S[i]=="o" and S[i+1]=="o" and S[i+2]=="-":
            print("O")
            flag=1
            break
    if flag:
        continue

    for i in range(N-3):
        if S[i]=="x" and S[i+1]=="o" and S[i+2]=="-" and S[i+3]=="-":
            S[i+2]="x"
            S[i+3]="o"

    for i in range(N-2):
        if S[i]=="-" and S[i+1]=="o" and S[i+2]=="o":
            print("O")
            flag=1
            break
    if flag:
        continue

    for i in range(N-1,2,-1):
        if S[i]=="x" and S[i-1]=="o" and S[i-2]=="-" and S[i-3]=="-":
            S[i-2]="x"
            S[i-3]="o"

    for i in range(N-2):
        if S[i]=="o" and S[i+1]=="o" and S[i+2]=="o":
            print("O")
            break
    else:
        print("X")