/* -*- coding: utf-8 -*-
 *
 * 126.cc: No.126 2基のエレベータ - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int a, b, s;
  cin >> a >> b >> s;

  int da = abs(a - s), db = abs(b - s);
  int ans;

  if (s == 1 || da <= db) ans = da + s;
  else if (a == 0) ans = db + s + 1;
  else ans = min(db + da + a, db + s - 1 + a);

  printf("%d\n", ans);
  return 0;
}