#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-9;

int main() {
	int R, G, B; cin >> R >> G >> B;
	vector<int> a(3);
	a[0] = R; a[1] = G; a[2] = B;
	int maxi = 0;
	for (int t = 0; t < 100000000; t++) {
		sort(a.begin(), a.end());
		maxi = max(maxi, a[0]);
		if (a[2] >= 2) {
			a[0]++; a[2] -= 2;
		}
	}
	cout << maxi << endl;
}