fn main() {
    let mut xx = String::new();
    std::io::stdin().read_line(&mut xx).ok();
    let xx: Vec<i64> = xx.split_whitespace().flat_map(str::parse).collect();

    let change = xx[2].min((xx[0] - xx[1]).abs());

    println!("{}", xx[0].min(xx[1]) + change + (xx[2] - change) / 2);
}