import sys
from collections import deque

input = sys.stdin.buffer.readline

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

dist = [None] * N
dist[0] = 0
d = deque([0])
dfs_order = []
is_leaf = [True] * N
while d:
    v = d.pop()
    dv = dist[v]
    for x, c in T[v]:
        if dist[x] is None:
            dfs_order.append((v, x))
            dist[x] = dv + c
            d.append(x)
            is_leaf[v] = False
desc_leaves = [int(l) for l in is_leaf]
for v, x in reversed(dfs_order):
    desc_leaves[v] += desc_leaves[x]

dp = [-10 ** 9] * (K + 1)
dp[0] = 0
for a, b, c in edges:
    new_dp = dp.copy()
    value = c * (min(desc_leaves[a], desc_leaves[b]))
    for i in range(K + 1 - c):
        new_dp[i + c] = max(new_dp[i + c], dp[i] + value)
    dp = new_dp
print(max(dp) + sum(ds * l for ds, l in zip(dist, is_leaf)))