#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

#define REP(i,s,n) for(int i=(int)(s);i<(int)(n);i++)

using namespace std;
typedef long long int ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef pair<int, int> PI;


int main(){
  int a,b,s;
  cin>>a>>b>>s;
  if (a <= b) {
    if (a > 0) {
      cout << min(abs(s - b), abs(s - a)) + s << endl;
    } else {
      cout << (abs(s - b) < abs(s - a) ? abs(s - b) + s + 1 : 2 * s) << endl;
    }
  } else if (s == 1) {
    cout << abs(a - 1) + 1 << endl;
  } else {
    cout << (abs(s - b) < abs(s - a) ? a + abs(s - b) + min(abs(s - a), s-1) : s + abs(s - a)) << endl;
  }
}