// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------

fn run() {
    input! {
        n: usize,
        k: usize,
        e: [(usize1, usize1, usize); n - 1],
    }
    let mut g = vec![vec![]; n];
    for (a, b, c) in e {
        g[a].push((b, c));
        g[b].push((a, c));
    }
    let mut topo = vec![0];
    for i in 0..n {
        let v = topo[i];
        for (u, _) in g[v].clone() {
            let x = g[u].iter().position(|e| e.0 == v).unwrap();
            g[u].remove(x);
            topo.push(u);
        }
    }
    let mut size = vec![0; n];
    let mut dp = vec![0; k + 1];
    for &v in topo.iter().rev() {
        if g[v].len() == 0 {
            size[v] = 1;
            continue;
        }
        for &(u, c) in g[v].iter() {
            let d = size[u];
            let w = c * d;
            for dp in dp.iter_mut() {
                *dp += w;
            }
            for i in (c..=k).rev() {
                dp[i] = dp[i].max(dp[i - c] + w);
            }
            size[v] += d;
        }
    }
    println!("{}", dp[k]);
}

fn main() {
    run();
}