import sys
import io, os
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline

n, k = map(int, input().split())
g = [[] for i in range(n)]
toc = {}
edge = []
for i in range(n-1):
    a, b, c = map(int, input().split())
    a, b = a-1, b-1
    g[a].append(b)
    g[b].append(a)
    toc[(a, b)] = c
    toc[(b, a)] = c
    edge.append((a, b, c))

s = []
s.append(0)
parent = [-1]*n
order = []
while s:
    v = s.pop()
    order.append(v)
    for u in g[v]:
        if parent[v] != u:
            s.append(u)
            parent[u] = v
order.reverse()
leaf = [0]*n
for v in order:
    if len(g[v]) == 1:
        leaf[v] = 1
    p =  parent[v]
    if p != -1:
        leaf[p] += leaf[v]
dp1 = [0]*n
for v in order:
    p =  parent[v]
    if p != -1:
        dp1[p] += dp1[v]+toc[(p, v)]*leaf[v]
#print(dp1)
dp2 = [-1]*(k+1)
dp2[0] = 0
for a, b, c in edge:
    if parent[a] == b:
        v = a
    else:
        v = b
    for i in reversed(range(k+1)):
        if dp2[i] == -1:
            continue
        if i+c <= k:
            dp2[i+c] = max(dp2[i+c], dp2[i]+c*leaf[v])
#print(dp2)
ans = dp1[0]+max(dp2)
print(ans)