N, K = map(int, input().split())

v = [[[], []] for _ in range(N)]
weight = []
for i in range(N-1):
    a, b, c = map(int, input().split())
    v[a-1][1].append((b-1, i))
    v[b-1][1].append((a-1, i))
    weight.append(c)
    
q = [(0, [])]
e = [0] * (N-1)
while len(q) > 0:
    i, c = q.pop(0)
    v[i][0] = c
    cnt = True
    for j, k in v[i][1]:
        if j == 0 or len(v[j][0]) > 0:
            continue
        cnt = False
        q.append((j, c+[k]))
    if cnt:
        for j in c:
            e[j] += 1         

dp = [[0] * (K+1)]
for i in range(N-1):
    dp.append([max(dp[i][w-weight[i]] + weight[i] * e[i] * 2, dp[i][w] + weight[i] * e[i]) if w >= weight[i] else (dp[i][w] + weight[i] * e[i]) for w in range(K+1)])

print(dp[N-1][K])