main = getLine >>= print . elevator . map read . words

elevator [a,b,s]
 | s == 1 = abs (s-a) + 1
 | abs (s-a) <= abs (s-b) = abs (s-a) + s
 | a > b = abs (s-b) + min (s-1) (abs (s-a)) + a 
 | otherwise = abs (s-b) + s + (if a == 0 then 1 else 0)