K_america_gp

#include <bits/stdc++.h>
#define int long long
#define pb push_back

using namespace std;
const int N = 2e5 + 10;
vector<int> gr[N];

int p[19][N], timer, tin[N], tout[N],n, q, d[N];

void dfs(int v, int pr, int ds = 0) {
    tin[v] = timer++;
    p[0][v] = pr;
    d[v] = ds;
    for(int i = 1; i <= 19; i++) {
        p[i][v] = p[i - 1][p[i - 1][v]];
    }
    for(auto it: gr[v]) {
        if(it != pr) dfs(it, v, ds + 1);
    }
    tout[v] = timer;
}

bool upper(int a, int b) {
    return tin[a] <= tin[b] && tout[a] >= tout[b];
}

int lca(int a, int b) {
    if(upper(a, b)) return a;
    if(upper(b, a)) return b;

    for(int i = 19; i >= 0; i--) {
        if(!upper(p[i][a], b)) {
            a = p[i][a];
        }
    }
    return p[0][a];
}

int len(int a, int b) {
    return d[a] + d[b] - 2 * d[lca(a, b)];
}
main() {
    cin >> n >> q;
    for(int i = 1; i < n; i++) {
        int l, r;
        cin >> l >> r;
        gr[l].pb(r);
        gr[r].pb(l);
    }
    dfs(1, 1);

    while(q--) {
        int l, r;
        cin >> l >> r;
        int dist = len(l, r) + 1;
        cout << dist * (dist + 1) / 2 + n - dist << endl;
    }

}