#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using ll =  long long ;
using P = pair<ll,ll> ;
const ll INF = 10000000000;
const int MOD = 1000000007;

int main(){
    int x,y,z;
    cin >> x >> y >> z;
    int ans = 0;
    if(x > y){
        ans += y;
        x -= y;
        y = 0;
        if(x > z){
            ans += z;
        }else{
            ans += (x+z)/2;
        }
    }else{
        ans += x;
        y -= x;
        x = 0;
        if(y > z){
            ans += z;
        }else{
            ans += (y+z)/2;
        }
    }
    cout << ans << endl;
    return 0;
}