#include<iostream>
#include<iomanip>
#include<string>
#include<algorithm>
#include<vector>
#include<set>
#include<list>
#include<queue>
#include<math.h>
#include<bitset>
using ll = long long;
using namespace std;

int main(){
    ll r, g, b, ans = 0;
    cin >> r >> g >> b;
    vector<ll> l = {r, g, b};
    sort(l.begin(), l.end());
    while ((l[0] != 0 && l[1] != 0 && l[2] != 0) || l[2] >= 3){
        ll t;
        sort(l.begin(), l.end());
        if (l[2] >= 3){
            l[0] += (l[2] - l[1])/2;
            l[2] -= (l[2] - l[1])/2*2;
        }
        t = *min_element(l.begin(), l.end());
        ans += t;
        l[0] -= t;
        l[1] -= t;
        l[2] -= t;
        if (l[0] == 0){
            t = l[1]/2;
            ans += t;
            l[1] -= t*2;
            l[2] -= t*2;
        }
    }
    cout << ans << endl;
}