fn main() {
    let input: Vec<usize> = read_vec();
    let mut output: usize = 0;

    if input[1] - input[0] + 1 < input[2] {
        output = input[1] - input[0] + 1;
    } else {
        output = input[2];
    }

    println!("{:?}", output);
}


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()
}