#include<bits/stdc++.h>
using lint=long long;
int main(){
    std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false);
    std::cout.setf(std::ios_base::fixed);std::cout.precision(15);
    std::vector<lint>a(3);
    for(lint&x:a)std::cin>>x;
    while(true){
        std::sort(a.begin(),a.end());
        if(a.back()-a.front()<3)break;
        a.front()++;
        a.back()-=2;
    }
    std::cout<<*std::min_element(a.begin(),a.end())<<'\n';
}