#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,y,z;
	cin>>x>>y>>z;
	if(x>y){
		swap(x,y);
	}
	int t=min(y-x,z);
	x+=t;
	z-=t;
	if(x==y){
		cout<<x+z/2<<endl;
	}else{
		cout<<x<<endl;
	}
	return 0;
}