n,Q=map(int,input().split())
e=[[] for i in range(n)]
for i in range(n-1):
  a,b=map(int,input().split())
  a-=1
  b-=1
  e[a]+=[b]
  e[b]+=[a]
v=[0]*n
u=[0]*n
p=[0]*n
q=[0]
while len(q)>0:
  s=q[-1]
  if v[s]==0:
    v[s]=1
    for t in e[s]:
      if t!=p[s]:
        q+=[t]
        p[t]=s
  else:
    u[s]=1
    for t in e[s]:
      if t!=p[s]:
        u[s]+=u[t]
    q.pop()
g=0
for i in range(Q):
  p,x=map(int,input().split())
  p-=1
  g+=u[p]*x
  print(g)