def dfs(G,v,p,sz,edge):
    cnt=0
    for nv,c in G[v]:
        if nv==p:
            continue
        cnt+=1
        dfs(G,nv,v,sz,edge)
        sz[v]+=sz[nv]
        edge.append([c,sz[nv]])
    if cnt==0:
        sz[v]=1


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

sz=[0]*N
edge=[]
dfs(G,0,-1,sz,edge)
ans=0
dp=[0]*(K+1)
for e,cnt in edge:
    ans+=e*cnt
    for i in range(K,-1,-1):
        if i-e<0:
            break;
        dp[i]=max(dp[i],dp[i-e]+cnt*e)
print(ans+max(dp))