use std::io::Read;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let mut cnt = vec![0; 11];
    for _ in 0..n {
        let a: usize = itr.next().unwrap().parse().unwrap();
        let b: usize = itr.next().unwrap().parse().unwrap();
        let c: usize = itr.next().unwrap().parse().unwrap();
        cnt[a] += 1;
        cnt[b] += 1;
        cnt[c] += 1;
    }

    let mut ans = 0;
    let mut rem = 0;
    for i in 1..11 {
        ans += cnt[i] / 2;
        rem += cnt[i] % 2;
    }
    ans += rem / 4;
    println!("{}", ans);
}