#include <bits/stdc++.h>

using namespace std;

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    ll R, G, B;
    std::cin >> R >> G >> B;

    // if minimizing, lb satisfies lb > ub
    // if maximizing, lb satisfies lb < ub
    int64_t lb = 0, ub = max({R, G, B}) + 1;

    while(std::abs(ub - lb) > 1){
        int64_t mid = (lb + ub) / 2;
        ll a = max(R - mid, 0ll) / 2 + max(G - mid, 0ll) / 2 + max(B - mid, 0ll) / 2, b = max(mid - R, 0ll) + max(mid - G, 0ll) + max(mid - B, 0ll);
        
        if(a >= b){
            lb = mid;
        }else{
            ub = mid;
        }
    }

    std::cout << lb << std::endl;
}