// ---------- begin next_permutation ----------
fn next_permutation<T: Ord>(a: &mut [T]) -> bool {
    a.windows(2).rposition(|a| a[0] < a[1]).map_or(false, |x| {
        let y = a.iter().rposition(|b| a[x] < *b).unwrap();
        a.swap(x, y);
        a[(x + 1)..].reverse();
        true
    })
}
// ---------- end next_permutation ----------
// ---------- begin scannner ----------
#[allow(dead_code)]
mod scanner {
    use std::str::FromStr;
    pub struct Scanner<'a> {
        it: std::str::SplitWhitespace<'a>,
    }
    impl<'a> Scanner<'a> {
        pub fn new(s: &'a String) -> Scanner<'a> {
            Scanner {
                it: s.split_whitespace(),
            }
        }
        pub fn next<T: FromStr>(&mut self) -> T {
            self.it.next().unwrap().parse::<T>().ok().unwrap()
        }
        pub fn next_bytes(&mut self) -> Vec<u8> {
            self.it.next().unwrap().bytes().collect()
        }
        pub fn next_chars(&mut self) -> Vec<char> {
            self.it.next().unwrap().chars().collect()
        }
        pub fn next_vec<T: FromStr>(&mut self, len: usize) -> Vec<T> {
            (0..len).map(|_| self.next()).collect()
        }
    }
}
// ---------- end scannner ----------

use std::io::Write;

fn main() {
    use std::io::Read;
    let mut s = String::new();
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut sc = scanner::Scanner::new(&s);
    let out = std::io::stdout();
    let mut out = std::io::BufWriter::new(out.lock());
    run(&mut sc, &mut out);
}

fn run<W: Write>(sc: &mut scanner::Scanner, out: &mut std::io::BufWriter<W>) {
    let n: usize = sc.next();
    let mut dp = vec![0; 1000000 + 1];
    let mut a = vec![];
    for _ in 0..n {
        let m: usize = sc.next();
        let mut p = vec![(0usize, 0usize); m];
        for p in p.iter_mut() {
            p.0 = sc.next();
            p.1 = sc.next();
            dp[p.0] = dp[p.0].max(p.1);
        }
        a.push(p);
    }
    let mut cond = vec![];
    for i in 0..dp.len() {
        if dp[i] > 0 {
            cond.push(i);
        }
    }
    for a in a.iter() {
        if a.len() == cond.len() && a.iter().all(|p| p.1 == dp[p.0]) {
            writeln!(out, "-1").ok();
            return;
        }
    }
    let mut ban = vec![];
    for a in a.iter() {
        let mut p = vec![];
        for a in a.iter() {
            if dp[a.0] == a.1 {
                p.push(a.0);
            }
        }
        if p.len() > 0 {
            ban.push(p);
        }
    }
    ban.sort();
    ban.dedup();
    for k in 2.. {
        let mut set = std::collections::BTreeSet::new();
        for ban in ban.iter() {
            if ban.len() >= k {
                let mut p = vec![0; ban.len()];
                for p in p.iter_mut().rev().take(k) {
                    *p = 1;
                }
                while {
                    let mut c = vec![];
                    for (i, p) in p.iter().enumerate() {
                        if *p > 0 {
                            c.push(ban[i]);
                        }
                    }
                    set.insert(c);
                    next_permutation(&mut p)
                } {}
            }
        }
        let mut test = vec![0; cond.len()];
        for t in test.iter_mut().rev().take(k) {
            *t = 1;
        }
        while {
            let mut x = vec![];
            for (i, t) in test.iter().enumerate() {
                if *t > 0 {
                    x.push(cond[i]);
                }
            }
            if !ban.contains(&x) {
                let mut ans = vec![vec![]; k];
                for a in a {
                    for (ans, &x) in ans.iter_mut().zip(&x) {
                        if !a.contains(&(x, dp[x])) {
                            ans.push(a.iter().fold(1, |s, a| s * a.0.pow(a.1 as u32)));
                            break;
                        }
                    }
                }
                writeln!(out, "{}", ans.len()).ok();
                for ans in ans {
                    write!(out, "{}", ans.len()).ok();
                    for a in ans {
                        write!(out, " {}", a).ok();
                    }
                    writeln!(out).ok();
                }
                return;
            }
            next_permutation(&mut test)
        } {}
    }
}