#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
#define all(x) x.begin(),x.end()
#define pb push_back
#define ll long long 
#define P pair<int,int>
#define LP pair<ll,ll>
using namespace std;
int main() {
	int a, b, c;
	int ans=0;
	cin >> a>>b>>c;
	if (a > b and b>0) {
		ans += b;
		for (int i = 1; i <= c; i++) {
			ans += 1;
			c -= 1;
			if (ans == a) break;
		}
	}
	else if (b > a and a>0) {
		ans += a;
		for (int i = 1; i <= c; i++) {
			ans += 1;
			c -= 1;
			if (ans == b) break;
		}
	}
	else if (a == 0 ) {
		for (int i = 1; i <= c; i++) {
			ans += 1;
			c -= 1;
			if (ans == b) break;
		}

	}
	else if (b == 0) {
		for (int i = 1; i <= c; i++) {
			ans += 1;
			c -= 1;
			if (ans == a) break;
		}

	}
	else 	ans += a;

	ans += c / 2;
	cout << ans << endl;
	return 0;
}