use std::collections::VecDeque;

use proconio::{input, marker::Usize1};

fn main() {
    input! {
        n:usize,
        a:[[Usize1];n],
    }

    let mut g = vec![vec![]; n];
    let mut rg = vec![vec![]; n];
    for i in 0..n {
        for &j in a[i].iter() {
            g[i].push(j);
            rg[j].push(i);
        }
    }

    let mut ord = vec![];
    let mut vis = vec![false; n];
    for i in 0..n {
        if vis[i] {
            continue;
        }
        dfs(i, &g, &mut vis, &mut ord);
    }

    ord.reverse();
    for i in 0..n {
        vis[i] = false;
    }

    let mut groups = vec![];
    let mut newvs = vec![0; n];
    let mut newv = 0;
    for &v in ord.iter() {
        if vis[v] {
            continue;
        }

        let mut group = vec![];
        dfs1(v, &rg, &mut vis, &mut group);
        for &u in group.iter() {
            newvs[u] = newv;
        }
        newv += 1;
        groups.push(group);
    }

    let newn = groups.len();
    let mut newg = vec![vec![]; newn];
    let mut newrg = vec![vec![]; newn];
    let mut indegs = vec![0; newn];
    for i in 0..n {
        for &j in a[i].iter() {
            if newvs[i] == newvs[j] {
                continue;
            }

            newg[newvs[i]].push(newvs[j]);
            newrg[newvs[j]].push(newvs[i]);
            indegs[newvs[j]] += 1;
        }
    }

    let mut q = VecDeque::new();
    for i in 0..newn {
        if indegs[i] == 0 {
            q.push_back(i);
        }
    }

    let mut topo = vec![];
    while let Some(crr) = q.pop_front() {
        topo.push(crr);
        for &nxt in newg[crr].iter() {
            if indegs[nxt] == 0 {
                continue;
            }

            indegs[nxt] -= 1;
            if indegs[nxt] == 0 {
                q.push_back(nxt);
            }
        }
    }

    topo.reverse();
    let mut dp = vec![0; newn];
    for i in 0..newn {
        for &j in newrg[topo[i]].iter() {
            dp[j] = dp[j].max(dp[topo[i]] + 1);
        }
    }
    let ans = dp[newvs[0]] + 1 == newn;
    println!("{}", if ans { "Yes" } else { "No" });
}

fn dfs(crr: usize, g: &Vec<Vec<usize>>, vis: &mut Vec<bool>, ord: &mut Vec<usize>) {
    vis[crr] = true;
    for &nxt in g[crr].iter() {
        if vis[nxt] {
            continue;
        }

        dfs(nxt, g, vis, ord);
    }

    ord.push(crr);
}

fn dfs1(crr: usize, g: &Vec<Vec<usize>>, vis: &mut Vec<bool>, group: &mut Vec<usize>) {
    vis[crr] = true;
    group.push(crr);
    for &nxt in g[crr].iter() {
        if vis[nxt] {
            continue;
        }

        dfs1(nxt, g, vis, group);
    }
}