{-# OPTIONS_GHC -O2 #-}

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

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