import sys
sys.setrecursionlimit(100000)

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)]
E = [[] for _ in range(N)]

for ab in AB:
    a,b = ab
    E[a-1].append(b-1)
    E[b-1].append(a-1)
dp = [0] * N

def dfs(x,p):
    cnt = 1
    for i in E[x]:
        if i != p:
            cnt += dfs(i,x)
    dp[x] = cnt
    return cnt

dfs(0,-1)
ans = 0
for px in PX:
    p,x = px
    ans += dp[p-1] * x
    print(ans)