n,k = map(int, input().split())
G = [[] for _ in range(n)]
for i in range(n-1):
  a,b,c = map(int, input().split())
  a -= 1
  b -= 1
  G[a].append((b,c))
  G[b].append((a,c))
check = [0]*n
check[0] = 1
stack = [0]
for i in range(n-1):
  for to,cost in G[stack[i]]:
    if check[to]:
      continue
    check[to] = 1
    stack.append(to)
dist = [[0,0] for _ in range(n)]
for i in range(n-1, -1, -1):
  check[stack[i]] = 0
  ex = 1
  for to,cost in G[stack[i]]:
    if check[to] == 1:
      continue
    ex = 0
    dist[stack[i]][0] += dist[to][0]
    dist[stack[i]][1] += dist[to][1] + dist[to][0]*cost
  dist[stack[i]][0] += ex
dp = [0]*(k+1)
for i in range(n):
  check[stack[i]] = 1
  for to,cost in G[stack[i]]:
    if check[to]:
      continue
    for j in range(k, cost-1, -1):
      if dp[j] < dp[j-cost] + cost*dist[to][0]:
        dp[j] = dp[j-cost] + cost*dist[to][0]
print(dist[0][1] + max(dp))