import sys
input = sys.stdin.readline

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

import copy

for S in Q:
    N=len(S)
    flag=0
    S2=copy.deepcopy(S)

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

    for i in range(N-3):
        if S[i]=="-" and S[i+1]=="o" and S[i+2]=="-" and S[i+3]=="-":
            print("O")
            flag=1
            break
        if S[i]=="-" and S[i+1]=="-" and S[i+2]=="o" and S[i+3]=="-":
            print("O")
            flag=1
            break
        
    if flag:
        continue

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

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

    S=S2

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

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

    print("X")