from collections import deque

def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    n = int(input[idx])
    idx += 1
    k = int(input[idx])
    idx += 1
    
    edges = [[] for _ in range(n + 1)]
    for _ in range(n - 1):
        a = int(input[idx])
        idx += 1
        b = int(input[idx])
        idx += 1
        c = int(input[idx])
        idx += 1
        edges[a].append((b, c))
        edges[b].append((a, c))
    
    parent = [-1] * (n + 1)
    depth = [0] * (n + 1)
    children = [[] for _ in range(n + 1)]
    visited = [False] * (n + 1)
    q = deque([1])
    visited[1] = True
    
    while q:
        u = q.popleft()
        for (v, c) in edges[u]:
            if not visited[v] and v != parent[u]:
                visited[v] = True
                parent[v] = u
                depth[v] = depth[u] + c
                children[u].append((v, c))
                q.append(v)
    
    leaves_count = [0] * (n + 1)
    
    def dfs(u):
        if not children[u]:
            leaves_count[u] = 1
            return 1
        total = 0
        for (v, _) in children[u]:
            total += dfs(v)
        leaves_count[u] = total
        return total
    
    dfs(1)
    
    items = []
    for u in range(1, n + 1):
        for (v, c) in children[u]:
            items.append((c, c * leaves_count[v]))
    
    dp = [0] * (k + 1)
    for cost, val in items:
        for j in range(k, cost - 1, -1):
            dp[j] = max(dp[j], dp[j - cost] + val)
    
    original_score = 0
    for u in range(1, n + 1):
        if not children[u]:
            original_score += depth[u]
    
    print(original_score + max(dp))

if __name__ == '__main__':
    main()