import Control.Applicative
import Control.Monad
import Data.Bits

readInts :: IO [Int]
readInts = map read . words <$> getLine

rightmost :: Int -> Int
rightmost n = length $ takeWhile (not . testBit n) [0..31]

swap :: Int -> Int -> Int -> Int
swap x n m = x `xor` a `xor` shift a d
  where
    d = m-n
    a = (shift x (-d) `xor` x) .&. shift 1 n

main = do
  n <- readLn
  m <- readLn
  query <- replicateM m readInts
  let
    query' = map (map (subtract 1)) query
    f [] s = 1 + rightmost s
    f ([p,q]:rs) s = f rs (swap s p q)
   in print $ f query' (shift 1 (n-1))