from sys import stdin
n, q, *indata = map(int, stdin.read().split())
offset = 0
g = [[] for i in range(n+1)]
for i in range(n-1):
    s, t = indata[offset + 2*i],indata[offset + 2*i+1]
    g[s].append(t)
    g[t].append(s)

dp = [0 for i in range(n+1)]
check = [0 for i in range(n+1)]
que = [(1,0)]
while que:
    now, inout = que.pop()
    if inout == 0:
        check[now] = 1
        que.append((now,1))
        for i in g[now]:
            if check[i] == 0:
                que.append((i,0))
    else:
        check[now] = 2
        dp[now] = 1
        for i in g[now]:
            if check[i] == 2:
                dp[now] += dp[i]

offset = (n-1) * 2
ans = 0
for i in range(q):
    p, x = indata[offset + 2*i],indata[offset + 2*i+1]
    ans += x * dp[p]
    print("{}".format(ans))