import sys

sys.setrecursionlimit(10000000)

N, Q = map(int, input().split())
AB = [list(map(int, input().split())) for _ in range(N - 1)]
PX = [list(map(int, input().split())) for _ in range(Q)]

G = [[] for _ in range(N + 1)]
order = [[-1, -1] for _ in range(N + 1)]

for a, b in AB:
    G[a].append(b)
    G[b].append(a)

p = -1


def dfs(v, pre=-1):
    global p
    p += 1
    order[v][0] = p
    for nx in G[v]:
        if nx == pre:
            continue
        dfs(nx, v)
    p += 1
    order[v][1] = p


dfs(1)
ans = []
tot = 0

for p, x in PX:
    tot += ((order[p][1] - order[p][0]) // 2 + 1) * x
    ans.append(tot)

print(*ans, sep="\n")