use std::collections::HashMap;

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

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 peak_max: usize = read();

    let mut peaks = HashMap::new();
    loop {
        let input: Vec<u32> = read_vec();
        {
            let e = peaks.entry(input[0]).or_insert(0);
            *e += 1;
        }
        {
            let e = peaks.entry(input[1]).or_insert(0);
            *e += 1;
        }
        if peaks.len() >= peak_max {
            break;
        }
    }

    let mut operation = 0;
    for (_peak, count) in &peaks {
        if *count > 2 {
            operation += *count - 2;
        }
    }

    println!("{}", operation);
}