#include <bits/stdc++.h>
#define rep(i,n)for(long long i=0;i<(n);i++)
using namespace std;
typedef long long ll;
const int MOD=1e9+7;
const int MAX = 1000000;
const int INF = 1e9;
const double pi=acos(-1);
using namespace std;

int main(){
  ll x,y,z;
  cin >> x>>y>>z;
  ll ans=0;
  rep(i,z+1){
    ans=max(ans,min(x+i,y+z-i));
  }
  cout << ans << endl;
  
  return 0;
}