n,K = map(int,input().split())
g = [[] for _ in range(n)]
for _ in range(n-1):
    a,b,c = map(int,input().split())
    g[a-1].append((b-1,c))
    g[b-1].append((a-1,c))
ans = 0

order = []
wt = [0]*n
st = [0]
parent = [-1]*n
while st:
    v = st.pop()
    order.append(v)
    for c,d in g[v]:
        if c != parent[v]:
            st.append(c)
            parent[c] = v
            wt[c] = d

res = []
size = [0]*n
for v in order[1:][::-1]:
    if len(g[v])==1: size[v] = 1
    ans += size[v]*wt[v]
    res.append((size[v],wt[v]))
    size[parent[v]] += size[v]

dp = [0]*(K+1)
for v,w in res:
    for i in range(w,K+1)[::-1]:
        dp[i] = max(dp[i], dp[i-w] + v*w)
print(ans+max(dp))