import os,sys,random,threading
#sys.exit() 退出程序
#sys.setrecursionlimit(10**6) #调整栈空间
from random import randint,choice,shuffle
#randint(a,b)从[a,b]范围随机选择一个数
#choice(seq)seq可以是一个列表,元组或字符串,从seq中随机选取一个元素
#shuffle(x)将一个可变的序列x中的元素打乱
from copy import deepcopy
from io import BytesIO,IOBase
from types import GeneratorType
from functools import lru_cache,reduce
#reduce(op,迭代对象)
from bisect import bisect_left,bisect_right
#bisect_left(x) 大于等于x的第一个下标
#bisect_right(x) 大于x的第一个下标
from collections import Counter,defaultdict,deque
from itertools import accumulate,combinations,permutations
#accumulate(a)用a序列生成一个累积迭代器，一般list化前面放个[0]做前缀和用
#combinations(a,k)a序列选k个 组合迭代器
#permutations(a,k)a序列选k个 排列迭代器
from heapq import  heapify,heappop,heappush
#heapify将列表转为堆
from typing import Generic,Iterable,Iterator,TypeVar,Union,List
from string import ascii_lowercase,ascii_uppercase,digits
#小写字母，大写字母，十进制数字
from math import ceil,floor,sqrt,pi,factorial,gcd,log,log10,log2,inf
#ceil向上取整，floor向下取整 ，sqrt开方 ，factorial阶乘
from decimal import Decimal,getcontext
#Decimal(s) 实例化Decimal对象,一般使用字符串
#getcontext().prec=100 修改精度
from sys import stdin, stdout, setrecursionlimit
input = lambda: sys.stdin.readline().rstrip("\r\n")
MI = lambda :map(int,input().split())
li = lambda :list(MI())
ii = lambda :int(input())
mod = int(1e9 + 7) #998244353
inf = 1<<60
py = lambda :print("YES")
pn = lambda :print("NO")
DIRS = [(0, 1), (1, 0), (0, -1), (-1, 0)]  # 右下左上
DIRS8 = [(0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1), (-1, 0),(-1, 1)]  # →↘↓↙←↖↑↗




class HLD:
    def __init__(self, g, root): 
        #无论是点还是dfn还是dep，都从1开始，默认0是无
        n=len(g)
        self.g=g
        self.fa=[0]*(n+5)   #父节点，0表示无父节点
        self.size=[1]*(n+5) #子树大小
        self.dep=[0]*(n+5)  #深度，根深度为1
        self.son=[0]*(n+5)  #重儿子，0表示无儿子
        self.dfn=[0]*(n+5)  #dfs序，子树终点的dfs序是dfn[i]+size[i]-1
        self.top=[0]*(n+5)  #所在重链起点，起点就是自己
        self.rank=[0]*(n+5) #dfs序为i的节点编号

        fa=self.fa;size=self.size;dep=self.dep;son=self.son
        dfn=self.dfn;top=self.top;rank=self.rank
        stk=[[root,0,0]] #node,flag,fa
        dep[root]=1
        while stk:
            u,flag,father=stk.pop()
            if flag:
                for v in g[u]:
                    if v!=father:
                        size[u]+=size[v]
                        if son[u]==0 or size[v]>size[son[u]]:
                            son[u]=v
            else:
                stk.append([u,1,father])
                for v in g[u]:
                    if v!=father:
                        stk.append([v,0,u])
                        fa[v]=u
                        dep[v]=dep[u]+1
        stk=[[root,root]]
        tot=1
        while stk:
            u,tops=stk.pop()
            dfn[u]=tot
            rank[tot]=u
            tot+=1
            top[u]=tops
            if son[u]==0:
                continue
            for v in g[u]:
                if v!=fa[u] and v!=son[u]:
                    stk.append([v,v])
            stk.append([son[u],tops])
    def lca(self,u,v):  #求u和v的最近公共祖先节点
        fa=self.fa;size=self.size;dep=self.dep;son=self.son
        dfn=self.dfn;top=self.top;rank=self.rank
        while top[u]!=top[v]:
            if dep[top[u]]>dep[top[v]]:
                u=fa[top[u]]
            else:
                v=fa[top[v]]
        return v if dep[u]>dep[v] else u
    
    def dis(self,u,v):
        dep=self.dep
        return dep[u]+dep[v]-2*dep[self.lca(u,v)]

    def kth_fa(self,root,k): #求root节点的第k个祖先
        fa=self.fa;size=self.size;dep=self.dep;son=self.son
        dfn=self.dfn;top=self.top;rank=self.rank
        if k>=dep[root]:   #无第k个祖先返回-1
            return -1           
        while True:
            u=top[root]
            if dfn[root]-k>=dfn[u]:
                return rank[dfn[root]-k]
            k-=dfn[root]-dfn[u]+1
            root=fa[u]

    
    def route_query(self,u,v): #查询u到v简单路径
        fa=self.fa;size=self.size;dep=self.dep;son=self.son
        dfn=self.dfn;top=self.top;rank=self.rank
        route=[]
        while top[u]!=top[v]:
            if dep[top[u]]<dep[top[v]]:
                u,v=v,u      
            route.append((dfn[top[u]],dfn[u]))
            u=fa[top[u]]
        if dep[u]>dep[v]:
            u,v=v,u
        route.append((dfn[u],dfn[v]))
        return route


def bootstrap(f, stack=[]):   #yield
    def wrappedfunc(*args, **kwargs):
        if stack:
            return f(*args, **kwargs)
        else:
            to = f(*args, **kwargs)
            while True:
                if type(to) is GeneratorType:
                    stack.append(to)
                    to = next(to)
                else:
                    stack.pop()
                    if not stack:
                        break
                    to = stack[-1].send(to)
            return to
    return wrappedfunc



n,q=li()

g=[[] for _ in range(n+1)]

for _ in range(n-1):
    u,v=li()
    g[u]+=[v]
    g[v]+=[u]

hld=HLD(g,1)
dep=hld.dep
size=hld.size
fa=hld.fa


for _ in range(q):
    u,v=li()
    if u==v:
        print(n)
        continue
    uv=hld.lca(u,v)
    dis=dep[u]+dep[v]-2*dep[uv]
    if dis%2==1:
        print(0)
    elif (dep[u]+dep[uv]-2*dep[uv])==dis//2:
        ku=hld.kth_fa(u,dis//2-1)
        kv=hld.kth_fa(v,dis//2-1)
        print(n-size[ku]-size[kv])
    elif (dep[u]+dep[uv]-2*dep[uv])>dis//2:
        ku=hld.kth_fa(u,dis//2-1)
        mid=fa[ku]
        print(size[mid]-size[ku])
    else:
        kv=hld.kth_fa(v,dis//2-1)
        mid=fa[kv]
        print(size[mid]-size[kv])