#include <bits/stdc++.h>
using namespace std;

int main(){
  int r,b,w;
  cin>>r>>b>>w;
  if(r==b){
    cout<<r+w/2<<endl;
    return 0;
  }
  
  if(r>b &&  r-b>=w){
    cout<<b+w<<endl;
    return 0;
  }
  if(r>b && r-b<w){
    cout<<r+(w-r+b)/2<<endl;
    return 0;
  }
  if(r<b &&  b-r>=w){
    cout<<r+w<<endl;
    return 0;
  }
  if(r<b && b-r<w){
    cout<<b+(w-b+r)/2<<endl;
    return 0;
  }    
  return 0;
}