def dfs(x,p):
  cnt=1
  for i in g[x]:
    if i!=p:
      cnt+=dfs(i,x)
    ans[x]=cnt
  return cnt
n,q=map(int,input().split())
g=[[] for i in range(n+1)]
for i in range(n-1):
  a,b=map(int,input().split())
  g[a].append(b)
  g[b].append(a)
ans=[0]*(n+1)
dfs(1,-1)
a=0
for i in range(q):
  p,x=map(int,input().split())
  a+=ans[p]*x
  print(a)