use std::io::*;
use std::str::FromStr;
use std::cmp::{min, max};

fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char) 
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

fn main() {
    let a: i64 = read();
    let b: i64 = read();
    let c: i64 = read();
    let d = min(a, b);
    let e = max(a, b) - min(a, b);
    let f = min(e, c);
    let g = (c - f) / 2;
    println!("{}", d + f + g);
}