const INF: isize = 1isize << 60;

fn main() {
    let mut nk = String::new();
    std::io::stdin().read_line(&mut nk).ok();
    let nk: Vec<usize> = nk.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nk[0];
    let k = nk[1];
    let mut avals = Vec::with_capacity(n);
    let mut bs = Vec::with_capacity(n);
    for i in 0..n {
        let mut am = String::new();
        std::io::stdin().read_line(&mut am).ok();
        let am: Vec<isize> = am.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        let a = am[0];
        let mut b = String::new();
        std::io::stdin().read_line(&mut b).ok();
        let b: Vec<usize> = b.trim().split_whitespace().map(|s| s.parse::<usize>().unwrap()-1).collect();
        avals.push(a);
        bs.push(b);
    }
    let mut paths = vec![vec![]; n];
    for u in 0..n {
        for &v in bs[u].iter() {
            paths[v].push((u, avals[v] - avals[u]));
        }
        if u+1 < n {
            paths[u].push((u+1, 0));
        }
    }
    let mut result = vec![INF; n];
    result[0] = 0;
    for u in 0..n {
        for &(v, cost) in paths[u].iter() {
            if v <= u { continue; }
            result[v] = result[v].min(result[u] + cost);
        }
    }
    println!("{}", -result[n-1]);
}