def tree_dfs(g, root=0):
    s = [root]
    d = [True] * len(g)
    d[root] = False
    order = []
    while s:
        p = s.pop()
        order.append(p)
        d[p] = False
        for node, _ in g[p]:
            if d[node]:
                s.append(node)
    return order

n, k = map(int, input().split())
g = [[] for _ in range(n)]
for i in range(n - 1):
    a, b, c = map(int, input().split())
    g[a - 1].append((b - 1, c))
    g[b - 1].append((a - 1, c))
order = tree_dfs(g)
d = [-1] * n
a = [0] * n
b = [0] * n
for v in order[::-1]:
    d[v] = 0
    for node, cost in g[v]:
        if d[node] != -1:
            d[v] += d[node]
            a[node] += d[node] * cost
            b[node] = cost
    if d[v] == 0:
        d[v] = 1
dp = [[0] * (k + 1) for _ in range(n + 1)]
for i in range(n):
    for j in range(k + 1):
        if j - b[i] >= 0:
            dp[i + 1][j] = max(dp[i][j - b[i]] + a[i], dp[i][j])
        else:
            dp[i + 1][j] = dp[i][j]
print(max(dp[n]) + sum(a))