from collections import deque
N, K = map(int, input().split())
X = [[] for i in range(N)]
for i in range(N-1):
    x, y, c= map(int, input().split())
    x, y = x-1, y-1 # 1-indexed
    X[x].append((y, c))
    X[y].append((x, c))

P = [-1] * N
Q = deque([0])
R = []
S = [0] * N
while Q:
    i = deque.popleft(Q)
    R.append(i)
    for a, c in X[i]:
        if a != P[i]:
            P[a] = i
            S[a] = c
            X[a].remove((i, c))
            deque.append(Q, a)

T = [0] * N
ans = 0
Y = []
for i in R[1:][::-1]:
    if not len(X[i]): T[i] += 1
    Y.append((S[i], S[i] * T[i]))
    ans += S[i] * T[i]
    T[P[i]] += T[i]

Z = [0] * (K + 1)
for y, v in Y:
    for i in range(K, y-1, -1):
        Z[i] = max(Z[i], Z[i-y] + v)
ans += Z[K]
print(ans)