mod = 1000000007
eps = 10**-9


def main():
    import sys
    from collections import deque
    input = sys.stdin.readline

    N, K = map(int, input().split())
    adj = [[] for _ in range(N+1)]
    for _ in range(N-1):
        a, b, c = map(int, input().split())
        adj[a].append((b, c))
        adj[b].append((a, c))

    que = deque()
    que.append(1)
    seen = [-1] * (N+1)
    seen[1] = 0
    par = [None] * (N+1)
    child = [[] for _ in range(N+1)]
    seq = []
    depth = [0] * (N+1)
    while que:
        v = que.popleft()
        seq.append(v)
        for u, c in adj[v]:
            if seen[u] == -1:
                seen[u] = seen[v] + 1
                par[u] = (v, c)
                child[v].append(u)
                que.append(u)
                depth[u] = depth[v] + c
    seq.reverse()

    D = 0
    for v in seq:
        if child[v]:
            continue
        D += depth[v]

    dp = [[D] * (K+1) for _ in range(N+1)]
    L = [0] * (N+1)
    for v in seq:
        if not child[v]:
            L[v] = 1
        else:
            for u in child[v]:
                L[v] += L[u]
        if v != 1:
            p, c = par[v]
            for j in range(K+1):
                dp[p][j] = max(dp[p][j], dp[v][j])
                if j + c <= K:
                    dp[p][j+c] = max(dp[p][j+c], dp[v][j] + c * L[v])
    print(max(dp[1]))


if __name__ == '__main__':
    main()