fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().split_whitespace()
        .map(|e| e.parse().ok().unwrap()).collect()
}

fn main() {
    let input: Vec<usize> = read_vec();
    let (l, r, m) = (input[0], input[1], input[2]);
    let ans = std::cmp::min(m, r - l + 1);
    println!("{}", ans);
}