module Main where

import Control.Monad (replicateM_)
import Data.List (group)
import Data.Map (Map, delete, fromListWith, (!?))

main :: IO ()
main = do
    cases <- readLn :: IO Int
    replicateM_ cases $ do
        _ <- getLine
        s <- getLine
        putStrLn $ if solve s then "YES" else "NO"

t1 = "RBY_YBR"
t2 = "X_Y__X"
t3 = "B_RRBR"
tests = [t1, t2, t3]

happyEnough :: String -> Bool
happyEnough = all ((>= 2) . length) . group . filter (/= '_')

freq :: String -> Map Char Int
freq = fromListWith (+) . map (\x -> (x, 1))

solve :: String -> Bool
solve s = happyEnough s || (bSpace && bAlpha)
  where
    fs = freq s
    bSpace = maybe False (>= 1) (fs !? '_')
    bAlpha = all (>= 2) $ delete '_' fs