{-# LANGUAGE FlexibleContexts, OverloadedStrings #-}
import Control.Applicative
import Control.Monad
import qualified Data.ByteString.Char8 as B
import Data.Maybe (fromJust)
import Text.Printf
import Debug.Trace

f :: Integer -> Integer -> Integer -> Integer
f a b x = (x `div` a) * (b - 1) + x

bisect :: (Integer -> Bool) -> (Integer,Integer) -> Integer
bisect f (b,e) =
  if e-b == 1 then e
  else
    let m = (b + e) `div` 2
    in if f m
       then bisect f (b,m)
       else bisect f (m,e)

main = do
  [a,b,c] <- getInts
  let g = \x -> f a b x >= c
  print $ bisect g (0,c+1)


-- util
getInts :: IO [Integer]
getInts = map (fst . fromJust . B.readInteger) . B.words <$> B.getLine