#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 5;
template<class T>
void rd(T &x){
    char c = getchar();
    int f =  1;
    for(;c>'9'||c<'0';c=getchar())
        if (c == '-') f = -1;
    for(x=0;c>='0'&&c<='9';c=getchar())
        x = x * 10 + (c - '0');
    x *= f;
}
int n;
vector<int>g[MAXN];
int sz[MAXN],fa[MAXN];
int dep[MAXN];
void dfs(int x, int ff){
    fa[x] = ff; 
    dep[x] = dep[ff] + 1;
    for (auto v : g[x])
        if (v != ff)
            dfs(v,x),sz[x] += sz[v];
    sz[x] ++;
}
int q;
int getlca(int x,int y){
    while(x != y){
        if (dep[x] > dep[y])
            x = fa[x];
        else y = fa[y];
    }
    return x;
}
#define ll long long 
vector<ll>getsize(int l,int r){
    vector<ll>res;
    if (l == r)
        return res;
    if (dep[l] < dep[r]){
        // lca x 
        int lastx = 0;
        while(r != l){
            res.push_back(sz[r] - sz[lastx]);
            lastx = r;
            r = fa[r];
        }
        reverse(res.begin(),res.end());
        return res;
    }

    int lastx = 0;
    while(l != r){
        res.push_back(sz[l] - sz[lastx]);
        lastx = l;
        l = fa[l];
    }
    return res;

}
int main(){
    rd(n);rd(q);
    for (int i = 1, x, y; i < n; i ++){
        rd(x);rd(y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1,0);
    for (int i  = 0; i < q; i ++){

            int x,y;
            rd(x);rd(y);
            int lca = getlca(x,y);
            vector<ll>sz1 = getsize(x,lca);
            vector<ll>sz2 = getsize(lca,y);
 
            if (x == lca){
                int fay = y;
                while(dep[fay] != dep[lca] + 1)
                    fay = fa[fay];
                sz1.push_back(n - fa[fay]);
            }
            
            else if (y == lca){
                int fax = x;
                while(dep[fax] != dep[lca] + 1)
                    fax = fa[fax];
                sz1.push_back(n  - sz[fax]);
            }
            else {
                
                int fax = x;
                while(dep[fax] != dep[lca] + 1)
                    fax = fa[fax];
                int fay = y;
                while(dep[fay] != dep[lca] + 1)
                    fay = fa[fay];
                sz1.push_back(n - sz[fax] - sz[fay]);
            }
            for (auto v : sz2)
                sz1.push_back(v);

            
            int Min = sz1.size() ;
            for (int i = 1 ; i < sz1.size(); i ++)
                sz1[i] += sz1[i-1];
            int nd = Min/2;
            long long ans =0;
            for (int i = 0; i + nd <Min; i ++)
                ans += (sz1.back() - sz1[i + nd]) * (i == 0 ? sz1[i] : (sz1[i] - sz1[i - 1]));
            printf("%lld\n",ans);
    } 
    return 0;
}