use std::io::{self, BufRead, BufReader};
use std::fs::File;

fn main() {
    let debug = false;

//    let f = File::open("src/input.txt").unwrap();
//    let mut f = BufReader::new(f);
    let stdin = io::stdin();
    let mut f = stdin.lock();

    let mut input_str = String::new();
    input_str.clear(); f.read_line(&mut input_str);
    let t: usize = input_str.trim().parse::<usize>().unwrap();
    if debug { println!("{}", t) }

    let queries: Vec<Vec<i32>> = f.lines()
        .filter_map(
            |l| l.ok().map(
                |s| s.split_whitespace()
                    .filter_map(|word| word.parse().ok())
                    .collect()
            )
        ).collect();
    if debug { println!("{:?}", queries) }
    for q in queries {
//        println!("{:?}", q);
        let b = q[0];
        let s = q[1];
        let c = q[2];
        for i in 2..c {
//            println!("{}", i);
            let t: i32 = b - i + s - i + i;
            if t == c {
                println!("{}", i);
            }
        }
    }
}