def dfs(start=0,goal=None):
    parents={}
    p,t=start,0
    parents[p]=-2
    next_set=[(~p,t),(p,t)]
    if p==goal:
        return t
    while next_set:
        p,t=next_set.pop()
        if p>=0:
            for q,d in edges[p]:
                if q in parents:
                    continue
                if q==goal:
                    return t+1
                parents[q]=p
                next_set.append((~q,t+1))
                next_set.append((q,t+1))
        else: # 帰りがけ処理
            p=~p
            if len(edges[p])==1 and p!=start:
                cnt[p]=1
            else:
                for q,d in edges[p]:
                    if q==parents[p]:
                        continue
                    cnt[p]+=cnt[q]
                    dp[q]=cnt[q]*d
                    cost_list.append(dp[q])
                    weight_list.append(d)

    return -1

def knapsack_weight(single=True):
    """
    重さが小さい時のナップサックDP
    :param single: True = 重複なし
    """
    """ dp[weight <= W] = 重さ上限を固定した時の最大価値 """
    N=len(weight_list)
    dp_min = 0  # 総和価値の最小値
    dp = [dp_min] * (W + 1)

    for item in range(N):
        if single:
            S = range(W, weight_list[item] - 1, -1)
        else:
            S = range(weight_list[item], W + 1)
        for weight in S:
            if dp[weight] < dp[weight - weight_list[item]] + cost_list[item]:
                dp[weight] = dp[weight - weight_list[item]] + cost_list[item]
    return dp[W]

N,K=map(int, input().split())
edges=[[] for _ in range(N)]
dp=[0]*N
cnt=[0]*N
for _ in range(N-1):
    a,b,c=map(int, input().split())
    a-=1
    b-=1
    edges[a].append((b,c))
    edges[b].append((a,c))

W = K
cost_list = []
weight_list = []

dfs(start=0,goal=None)
S=sum(dp)

print(S+knapsack_weight(single=True))