import Control.Monad (replicateM)
import Data.List (group, sort)
import qualified Data.ByteString.Char8 as B

solve :: Int -> [String] -> Bool
solve n xs = m <= ((n+1) `div` 2)
    where
        m = maximum . map length . group . sort $ xs

main :: IO ()
main = do
    n  <- readLn :: IO Int
    xs <- replicateM n $ B.getLine
    putStrLn $ if solve n (map B.unpack xs) then "YES" else "NO"