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

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()
}