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

fn main() {
    input! {
        n:usize,
        k:usize,
        uvw:[(Usize1,Usize1,usize);n-1],
    }

    let mut g = vec![vec![]; n];
    for &(u, v, _) in uvw.iter() {
        g[u].push(v);
        g[v].push(u);
    }
    let mut deps = vec![0; n];
    let mut leefs = vec![0; n];
    f(0, n, 0, &g, &mut deps, &mut leefs);

    let mut dp = vec![vec![0; k + 1]; n];
    for (i, &(u, v, w)) in uvw.iter().enumerate() {
        for j in 0..=k {
            let r = if deps[u] < deps[v] { v } else { u };
            dp[i + 1][j] = dp[i + 1][j].max(dp[i][j] + w * leefs[r]);
            if j + w <= k {
                dp[i + 1][j + w] = dp[i + 1][j + w].max(dp[i][j] + 2 * w * leefs[r]);
            }
        }
    }

    let ans = *dp[n - 1].iter().max().unwrap();
    println!("{}", ans);
}

fn f(
    crr: usize,
    prv: usize,
    dep: usize,
    g: &Vec<Vec<usize>>,
    deps: &mut Vec<usize>,
    leefs: &mut Vec<usize>,
) {
    deps[crr] = dep;
    for &nxt in g[crr].iter() {
        if nxt == prv {
            continue;
        }

        f(nxt, crr, dep + 1, g, deps, leefs);
        leefs[crr] += leefs[nxt];
    }
    if crr != 0 && g[crr].len() == 1 {
        leefs[crr] = 1;
    }
}