proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  while true:
    let k = getchar_unlocked()
    if k < '0': break
    result = 10 * result + k.ord - '0'.ord

var a = scan()
var b = scan()
var s = scan()
var ans = 0
while s != 0:
  if s == 1 or abs(s-a) <= abs(s-b) :
    ans += abs(s-a) + s
    break
  if b > a : # Aの階へ
    ans += abs(s-b) + abs(s-a)
    s = a
    b = a
  else: # 中間:abs(s-a) == abs(s-b)へ
    ans += abs(s-b)
    s += 1
    b += 1
echo ans