#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>

#define FORR(i,b,e) for(int i=(b);i<(int)(e);++i)
#define FOR(i,e) FORR(i,0,e)
#define sortuniq(v) sort(v.begin(), v.end()), v.erase(unique(v.begin(),v.end()),v.end())
#define dump(var) cerr << #var ": " << var << "\n"
#define dumpc(con) for(auto& e: con) cerr << e << " "; cerr<<"\n"

typedef long long ll;
typedef unsigned long long ull;

const double EPS = 1e-6;
const int d4[] = {0, -1, 0, 1, 0};

using namespace std;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int A, B, S;
    cin >> A >> B >> S;

    int da = abs(A-S), db = abs(B-S);

    if (S != 1 && da > db) {
        if (da < S - 1) cout << db + da + A;
        else cout << db + S - 1 + abs(1-A) + 1;
    }
    else {
        cout << da + S;
    }
    cout << endl;
    
    return 0;
}