#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <climits>
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <stack>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <sstream>
#include <functional>
#include <ctime>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n)  FOR(i,0,n)
#define CLEAR(d) memset((d), 0, (sizeof((d))))
#define ALL(c) (c).begin(), (c).end()
#define ABS(x) ((x < 0) ? -(x) : (x))
#define SORT(x) sort((x).begin(), (x).end())
#define RSORT(x) sort((x).begin(), (x).end(), greater<int>() )
#define SIZE(a) ((int)((a).size()))
#define MOD 1000000007
#define EPS 1e-10
#define PI  (acos(-1))
#define INF 10000000
struct edge { int to; int cost; };
//===================================================

int main()
{
    int r, g, b, ans = 0;
    cin >> r >> g >> b;
    int m = min(r, min(g, b));
    ans += m; r -= m; g -= m; b -= m;
    while (1) {
        int t[3] = { 0 };
        if (r >= 3 && r >= g && r >= b) t[0] -= 2;
        else if (g >= 3 && g >= r && g >= b) t[1] -= 2;
        else if (b >= 3 && b >= r && b >= g) t[2] -= 2;
        else break;
        if (r <= g && r <= b) t[0] += 1;
        else if (g <= r && g <= b) t[1] += 1;
        else if (b <= r && b <= g) t[2] += 1;
        r += t[0]; g += t[1]; b += t[2];
        if (r >= 1 && g >= 1 && b >= 1) {
            r--; g--; b--;
            ans++;
        }
    }
    cout << ans << endl;
    return 0;
}