#include <bits/stdc++.h>
using namespace std;

#include  <ext/pb_ds/assoc_container.hpp>
#include  <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T>
using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define RALL(a) a.rbegin(), a.rend()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long ll;
typedef double db;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<double> vd;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef pair<long long, long long> pll;
typedef vector<pair<int, int> > vpii;
typedef vector<pair<long long, long long> > vpll;
typedef set<int> si;
typedef set<long long> sll;
typedef map<int, int> mii;
typedef map<long long, long long> mll;

#ifdef ONPC
mt19937 rnd(228);
#else
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
#endif

constexpr int INF = 1e9 + 47;
constexpr long long LINF = (ll) 1e18 + 4747;
constexpr int MOD = 998244353;
constexpr int N = 1e5 + 47;

int solve()
{
	int n, r, k;
	if (!(cin >> n >> r >> k))
		return 1;
	
	if (max(r, k) >= n)
	{
		cout << max(r, k) * 2 << '\n';
	}
	else
	{
		int ans = r + n;
		if (ans & 1)
			ans++;
		cout << ans << '\n';
	}
	
	return 0;
}

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int TET = 1e9;
    //cin >> TET;
    for (int i = 1; i <= TET; i++)
    {
        if (solve())
        {
            break;
        }
#ifdef ONPC
        cout << "__________________________" << endl;
#endif
    }
#ifdef ONPC
    cerr << endl << "finished in " << clock() * 1.0 / CLOCKS_PER_SEC << " sec" << endl;
#endif

    return 0;
}