use std::collections::VecDeque;
use std::io::*;

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 q: Vec<VecDeque<usize>> = vec![VecDeque::new(); n];
    for i in 0..n {
        let p: usize = itr.next().unwrap().parse().unwrap();
        for _ in 0..p {
            let a: usize = itr.next().unwrap().parse().unwrap();
            q[i].push_back(a);
        }
    }

    let mut out = Vec::new();
    loop {
        let mut ok = false;
        for i in 0..n {
            if let Some(x) = q[i].pop_front() {
                ok = true;
                write!(out, "{} ", x).ok();
            }
        }
        if !ok {
            break;
        }
    }
    let m = out.len();
    out[m - 1] = '\n' as u8;
    stdout().write_all(&out).unwrap();
}