program main
  implicit none
  integer::A,B,S,move=0
  read *,A,B,S
  if(A.eq.0) then
     move = move + 1
     A    = 1
  end if

  if(S.eq.1) then
     move = move + A
  else if(ABS(B-S).lt.ABS(A-S)) then
     if(B.lt.A) then
        move = move + ABS(B-S) + MIN((S-1),ABS(A-S)) + A
     else
        move = move + ABS(B-S) + ABS(S-A) + A
     end if
  else
     move = move + ABS(A-S) + S
  end if
  print '(i0)', move
end program main