import sys
input = sys.stdin.readline

N,K=map(int,input().split())

E=[tuple(map(int,input().split())) for i in range(N-1)]

EDGE=[[] for i in range(N)]

for a,b,e in E:
    a-=1
    b-=1
    EDGE[a].append((b,e))
    EDGE[b].append((a,e))

QUE=[0] 
Parent=[-1]*(N+1)
Parent[0]=0
TOP_SORT=[]

while QUE:
    x=QUE.pop()
    TOP_SORT.append(x)
    for to,w in EDGE[x]:
        if Parent[to]==-1:
            Parent[to]=x,w
            QUE.append(to)

EW=[0]*N

for n in TOP_SORT[1:][::-1]:
    if EW[n]==0:
        EW[n]=1
    EW[Parent[n][0]]+=EW[n]

XX=[]
for i in range(1,N):
    XX.append((Parent[i][1],EW[i]))

ANS=0

for x,c in XX:
    ANS+=x*c

cost=0
DP=[0]*(K+1)

for x,c in XX:
    for j in range(K,-1,-1):
        if j+x<=K:
            DP[j+x]=max(DP[j+x],DP[j]+x*c)
print(max(DP)+ANS)