#include "testlib.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define all(a) begin(a), end(a)
#define space inf.readChar(' ')
#define endl inf.readChar('\n')
#define eof inf.readEof()
tuple<ll> read(ll min, ll max){
    ll a = inf.readLong(min, max);
    endl;
    return tuple{a};
}
template<class... T> auto read(ll min, ll max, T... t){
    ll a = inf.readLong(min, max);
    space;
    return tuple_cat(tuple{a}, read(t...));
}
string read(string p){
    return inf.readLine(p);
}
vector<ll> reads(ll N, ll min, ll max){
    auto a = inf.readLongs(N, min, max);
    endl;
    return a;
}
vector<string> read_lines(ll N, string p){
    return inf.readLines(N, p);
}
template<class... T> auto read_lines(ll N, T... t){
    vector<decltype(read(t...))> a;
    a.reserve(N);
    while(N--) a.push_back(read(t...));
    return a;
}
vector<vector<ll>> read_matrix(ll H, ll W, ll min, ll max){
    vector<vector<ll>> ans(H);
    for(auto& v : ans) v = reads(W, min, max);
    return ans;
}

const int MIN_N = 3;
const int MAX_N = 20000;
const int MAX_Q = 10000;

struct DSU {
    vector<int> parent;
    DSU(int n) {
        parent.resize(n);
        iota(parent.begin(), parent.end(), 0);
    }
    int find(int i) {
        if (parent[i] == i)
            return i;
        return parent[i] = find(parent[i]);
    }
    bool unite(int i, int j) {
        int root_i = find(i);
        int root_j = find(j);
        if (root_i != root_j) {
            parent[root_i] = root_j;
            return true;
        }
        return false;
    }
};

int main() {
    registerValidation();
    int N = inf.readInt(MIN_N, MAX_N);
    inf.readSpace();
    long long max_q_limit = min((long long)MAX_Q, 1LL * N * (N - 1) / 2);
    int Q = inf.readInt(1, max_q_limit);
    inf.readEoln();

    DSU dsu(N);
    set<pair<int, int>> edges;

    for (int i = 0; i < N - 1; ++i) {
        int u = inf.readInt(0, N - 1);
        inf.readSpace();
        int v = inf.readInt(0, N - 1);
        inf.readEoln();

        ensure(u != v);
        int min_v = min(u, v);
        int max_v = max(u, v);
        ensure(edges.insert({min_v, max_v}).second);
        ensure(dsu.unite(u, v));
    }

    for (int i = 0; i < Q; ++i) {
        int u = inf.readInt(0, N - 1);
        inf.readSpace();
        int v = inf.readInt(0, N - 1);
        inf.readEoln();

        ensure(u != v);
        int min_v = min(u, v);
        int max_v = max(u, v);
        ensure(edges.insert({min_v, max_v}).second);
    }

    inf.readEof();
}