//
// Stvoreno Energom o 24.10.23. 11:47:18
//

#include <bits/stdc++.h>

#define F first
#define S second
#define MP make_pair
#define PB push_back

#define all(a) a.begin(), a.end()
#define len(a) (int) (a.size())
#define fir first
#define sec second
#define mp make_pair
#define pb push_back

using namespace std;

#ifdef Energy_is_not_over
#define DEBUG for (int _____DEBUG=1;_____DEBUG;_____DEBUG=0)
#define LOG(...) print(#__VA_ARGS__" ::",__VA_ARGS__)<<endl

template<class ...Ts>
auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }

#else
#define DEBUG while (0)
#define LOG(...)
#endif

typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;

const int max_n = 1000111, inf = 1000111222;
const int max_lev = 20;

long long solve(const vector<int> &sz) {
    if (sz.size() <= 2) {
        return 0;
    }
    long long sum = 0;
    int pos = sz.size() - 1;
    while (pos > int(sz.size()) - pos) {
        sum += sz[pos--];
    }
    long long res = 0;
    for (int i = 0; i < sz.size() && pos + 1 < sz.size(); ++i) {
        res += 1LL * sz[i] * sum;
        ++pos;
        sum -= sz[pos];
    }
    return res;
}

int n, q;
vector<int> g[max_n];

vector<int> sz1, sz2;

struct tree {
    int p[max_lev][max_n], tin[max_n], tout[max_n], curt, sz[max_n];

    void init() {
        curt = -1;
        dfs(0);
        get_all_p();
    }

    void dfs(int v) {
        tin[v] = ++curt;
        sz[v] = 1;
        for (int to : g[v]) {
            if (to == p[0][v]) {
                continue;
            }
            p[0][to] = v;
            dfs(to);
            sz[v] += sz[to];
        }
        tout[v] = curt;
    }

    bool is_ancestor(int u, int v) {
        return tin[u] <= tin[v] && tout[u] >= tout[v];
    }

    int lca(int u, int v) {
        if (is_ancestor(u, v)) {
            return u;
        }
        for (int lev = max_lev - 1; lev >= 0; --lev) {
            if (!is_ancestor(p[lev][u], v)) {
                u = p[lev][u];
            }
        }
        return p[0][u];
    }

    void get_all_p() {
        for (int lev = 1; lev < max_lev; ++lev) {
            for (int i = 0; i < n; ++i) {
                p[lev][i] = p[lev - 1][p[lev - 1][i]];
            }
        }
    }

    template<bool lca_incl>
    int proc(int v, int lc, vector<int> &szs) {
        int last = 0;
        while (true) {
            if (v == lc && !lca_incl) {
                break;
            }
            szs.push_back(sz[v] - last);
            last = sz[v];
            if (v == lc) {
                break;
            }
            v = p[0][v];
        }
        return last;
    }

    long long solve(int u, int v) {
        int lc = lca(u, v);
        sz1.clear();
        sz2.clear();
        proc<true>(u, lc, sz1);
        sz1.back() -= proc<false>(v, lc, sz2);
        sz1.back() += n - sz[lc];
        reverse(sz2.begin(), sz2.end());
        sz1.insert(sz1.end(), sz2.begin(), sz2.end());
        return ::solve(sz1);
    }
};

tree t;

int main() {
//    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> q;
    for (int i = 1; i < n; ++i) {
        int u, v;
        cin >> u >> v;
        --u;
        --v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    t.init();
    while (q--) {
        int u, v;
        cin >> u >> v;
        --u;
        --v;
        cout << t.solve(u, v) << "\n";
    }
    return 0;
}