#include<bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pf push_front
#define LC k<<1
#define RC k<<1|1
#define IO cin.sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define all(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define rep(i, a, n) for (int i = a; i < n; i++)
#define repn(i, a, n) for (int i = a; i <= n; i++)
#define per(i, a, n) for (int i = (n) - 1; i >= a; i--)
#define pern(i, a, n) for (int i = n; i >= a; i--)

typedef long long LL;
typedef long double LD;
typedef unsigned long long ull;
typedef pair<int, int> PII;
typedef pair<int, LL> PIL;
typedef pair<LL, int> PLI;
typedef pair<double, double> PDD;
typedef pair<ull, ull> PUU;
typedef pair<LL, LL> PLL;

const int N = 210000;
const int M = 1100000;
const int mod = 1e9+7;
const int inf = (int)1e9;
const LL INF = 1e18;
const double eps = 1e-9;

mt19937_64 Rand((unsigned long long)new char);
#define rand Rand

const int L = 400;
int n, q, arr[N], l[N], r[N], cnt, v[N];
vector<PII> g[N];
int blk[N], sum[N], ans[N], num[N];
void dfs(int x, int fa) {
	l[x] = ++cnt, arr[cnt] = x;
	for (auto p: g[x]) {
		int y = p.fi, w = p.se;
		if (y == fa) continue;
		v[y] = w;
		dfs(y, x);
	}
	r[x] = ++cnt, arr[cnt] = x;
}
struct query {
	int l, r, id;
	friend bool operator < (query a, query b) {
		if (a.l / L != b.l / L) return a.l / L < b.l / L;
		if ((a.l / L) & 1) return a.r > b.r;
		else return a.r < b.r;
	}
}a[N];
void inc(int x) {
	x = arr[x];
	int w = v[x];
	if (v[x] > n) return;
	num[x]++;
	if (num[x] % 2 == 0) {
		blk[w]--;
		if (blk[w] == 0) sum[w / L]--;
	}
	else {
		blk[w]++;
		if (blk[w] == 1) sum[w / L]++;
	}
}
void dec(int x) {
	x = arr[x];
	int w = v[x];
	if (v[x] > n) return;
	num[x]--;
	if (num[x] % 2 == 0) {
		blk[w]--;
		if (blk[w] == 0) sum[w / L]--;
	}
	else {
		blk[w]++;
		if (blk[w] == 1) sum[w / L]++;
	}
}
void work() {
	int l = 1, r = 1;
	repn(i, 1, q) {
		while (r < a[i].r) inc(++r);
		while (l > a[i].l) dec(l--);
		while (r > a[i].r) dec(r--);
		while (l < a[i].l) inc(++l);
		for (int j = 0; ; j++) {
			if (sum[j] != L) {
				int cur = j * L;
				while (blk[cur]) cur++;
				ans[a[i].id] = cur;
				break;
			}
		}
	}
}
int main() {
	IO;
	cin >> n >> q;
	rep(i, 1, n) {
		int x, y, w;
		cin >> x >> y >> w;
		g[x].pb(mp(y, w));
		g[y].pb(mp(x, w));
	}
	v[1] = inf;
	dfs(1, 0);
	repn(i, 1, q) {
		int x, y;
		cin >> x >> y;
		if (l[x] > l[y]) swap(x, y);
		a[i] = {l[x], l[y], i};
	}
	sort(a + 1, a + q + 1);
	work();
	repn(i, 1, q) cout << ans[i] << "\n";
	return 0;
}