fn dfs(cur: usize, prev: usize, paths: &Vec<Vec<(usize, usize)>>, leaves: &mut Vec<usize>) -> usize {
    let mut flg = false;
    let mut ret = 0usize;
    for &(v, _) in paths[cur].iter() {
        if v == prev { continue; }
        flg = true;
        ret += dfs(v, cur, paths, leaves);
    }
    if !flg {
        ret += 1;
    }
    leaves[cur] = ret;
    ret
}

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 lines = Vec::with_capacity(n-1);
    let mut paths = vec![vec![]; n];
    for _ in 0..n-1 {
        let mut temp = String::new();
        std::io::stdin().read_line(&mut temp).ok();
        let temp: Vec<usize> = temp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        let a = temp[0]-1;
        let b = temp[1]-1;
        let c = temp[2];
        paths[a].push((b, c));
        paths[b].push((a, c));
        lines.push((a, b, c));
    }

    let mut leaves = vec![0usize; n];
    dfs(0, 0, &paths, &mut leaves);
    let mut dp = vec![vec![0usize; k+1]; n];
    let mut score = 0usize;
    for i in 0..n-1 {
        let (a, b, c) = lines[i];
        let addval = c * leaves[a].min(leaves[b]);
        score += addval;
        for j in 0..=k {
            dp[i+1][j] = dp[i+1][j].max(dp[i][j]);
            if j+c <= k {
                dp[i+1][j+c] = dp[i+1][j+c].max(dp[i][j] + addval);
            }
        }
    }
    println!("{}", dp[n-1][k] + score);
}