import Control.Applicative ((<$>), (<*>))
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B
import System.IO (hFlush, stdout)
import Data.List (foldl')
import Data.Char (isSpace)
import Data.Vector (Vector, (!), (//))
import qualified Data.Vector as V

main :: IO ()
main = do
  n <- readi B.readInt <$> B.getLine
  solve n <$> readiv B.readInt <$> B.getLine >>= mapM putStrLn
  hFlush stdout
  B.getLine
  return ()
  
solve :: Int -> Vector Int -> [String]
solve n v = show (length rs) : (reverse rs)
  where ids = [(j, j+1) | i <- [n-2, n-3 .. 0], j <- [0 .. i]]
        f (tv, rs) (i, j) | (tv ! i) <= (tv ! j) = (tv, rs)
                          | otherwise = (tv // [(i, tv ! j), (j, tv ! i)], unwords [show i, show j] : rs)
        (_, rs) = foldl' f (v, []) ids

readi :: Integral a =>  (ByteString -> Maybe (a, ByteString)) -> ByteString -> a
readi f s = let Just (n, _) = f s in n

readiv :: Integral a =>  (ByteString -> Maybe (a, ByteString)) -> ByteString -> Vector a
readiv f = V.unfoldr g
  where g s = do
          (n, s') <- f s
          return (n, B.dropWhile isSpace s')