from sys import stdin

readline = stdin.readline

N, K = map(int, readline().split())
links = [{} for _ in range(N)]
for _ in range(N - 1):
    a, b, c = map(int, readline().split())
    a, b = a - 1, b - 1
    links[a][b] = c
    links[b][a] = c

def dfs1(n):
    l = links[n]
    for x in l:
        del links[x][n]
    for x in l:
        dfs1(x)
dfs1(0)

result = 0
t = []
def dfs2(n):
    global result
    l = links[n]
    if len(l) == 0:
        return 1
    c = 0
    for x in l:
        a = dfs2(x)
        c += a
        t.append((l[x], a))
        result += l[x] * a
    return c
dfs2(0)

dp = [-1] * (K + 1)
dp[0] = 0
for i in range(len(t)):
    for j in range(K - 1,  -1, -1):
        if dp[j] == -1:
            continue
        a = j + t[i][0]
        if a > K:
            continue
        dp[a] = max(dp[a], dp[j] + t[i][0] * t[i][1])
result += max(dp)
print(result)