N,K = map(int,input().split())
lsg = [[] for i in range(N)]
h = []
for i in range(N-1):
    a,b,c = map(int,input().split())
    a -= 1
    b -= 1
    h.append((a,b,c))
    lsg[a].append((b,c))
    lsg[b].append((a,c))

dp = [0]*(N)
def dfs(k,p): #node k につながっている葉の数。
    if p >= 0 and len(lsg[k]) == 1:
        dp[k] = 1
        return 1
    ret = 0
    for j,c in lsg[k]:
        if j == p:
            continue
        ret += dfs(j,k)
    dp[k] = ret
    return ret
dfs(0,-1)
scores = []
ans = 0
for i in range(N-1):
    a,b,c = h[i]
    g = min(dp[a],dp[b])*c
    scores.append((c,g))
    ans += g
dp2 = [0]*(K+1)
for i in range(N-1):
    c,g = scores[i]
    dp3 = [0]*(K+1)
    for j in range(K+1):
        if j + c <= K:
            dp3[j+c] = max(dp2[j]+g,dp2[j+c])
        dp3[j] = max(dp2[j],dp3[j])
    dp2 = dp3
print(ans+max(dp2))