#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);

    int ans = 0;
    vector<int> A(3); rep(i,3) cin >> A[i];
    
    while(true) {
        int res = *min_element(A.begin(), A.end());
        rep(i,3) A[i] -= res;
        int argMax = max_element(A.begin(), A.end()) - A.begin();
        int argMin = min_element(A.begin(), A.end()) - A.begin();
        if(argMax == argMin || A[argMax] <= 1) { ans += res; break; }
        else {
            A[argMax] -= 2;
            A[argMin] += 1;
            ans += res;
        }
    }

    cout << ans << endl;
}