judge :: Int -> String -> String
judge 1 _ = "NO"
judge 2 s = if s == "00" || s == "11" then "YES" else "NO"
judge 3 s = if s == "010" || s == "101" then "NO" else "YES"
judge _ _ = "YES"

main :: IO ()
main = do
    n <- readLn :: IO Int
    if n >= 4
        then putStrLn "YES"
        else putStrLn . judge n =<< getLine