#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(){
  int r,g,b;
  cin>>r>>g>>b;
  vector<int> v;
  v.push_back(r);
  v.push_back(g);
  v.push_back(b);
  while(1){
    sort(v.begin(),v.end(),greater<int>());
    if(v[0]-v[2]<3){
      break;
    } else {
      v[0]-=2;
      v[2]+=1;
    }
  }
  cout<<v[2]<<endl;
  return 0;
}