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

int main(){
    int a,b,c,d;
    cin>>a>>b>>c;
    d=max(a,b);
    if(d-min(a,b)>=c){
        cout<<min(a,b)+c;
        return 0; 
    }
    else{
        c-=d-min(a,b);
        d+=c/2;
        cout<<d;
    }
    return 0;
}