#include <bits/stdc++.h>

using u32 = unsigned;
using i64 = long long;
using u64 = unsigned long long;

constexpr int N = 2E5 + 5;

int n, q, val[N], id[N], dfn[N], _tot, tot, f[N], g[N];
int tofa[N];
std::vector<std::array<int, 2>> adj[N];
int st[N][20], bel[N], B;

int get(int x, int y) {
	return dfn[x] < dfn[y] ? x : y;
}
void dfs(int x, int fa) {
	st[dfn[x] = ++_tot][0] = fa;
	id[f[x] = ++tot] = x;
	for (auto [v, w] : adj[x]) {
		if (v == fa) continue;
		tofa[v] = w;
		dfs(v, x);
	}
	id[g[x] = ++tot] = x;
}
int getlca(int u, int v) {
	if (u == v) return u;
	if ((u = dfn[u]) > (v = dfn[v])) std::swap(u, v);
	int d = std::__lg(v - u++);
	return get(st[u][d], st[v - (1 << d) + 1][d]);
}

int ans[N], cnt[N];

struct Query {
	int l, r;
	int idx;
	bool operator<(const Query& w) const {
		return bel[l] == bel[w.l] ? r < w.r : l < w.l;
	}
} b[N];

struct Div {
	int cnts[N], KB;
	int pos[N], maxsz[N];
	void ins(int p) {
		if (p > n) return ;
		++cnts[p / KB];
		pos[p]++;
	}
	void del(int p) {
		if (p > n) return ;
		--cnts[p / KB];
		pos[p]--;
	}
	void init() {
		KB = std::sqrt(n + 1);
		for (int i = 0; i <= n / KB; ++i)
			maxsz[i / KB]++;
	}
	int qry() {
		int i, j; 
		for (i = 0; i <= n / KB && cnts[i] == maxsz[i]; ++i) ;
		for (j = i * KB; j <= n && pos[j]; ++j) ;
		return j;
	}
} dv;

bool vis[N];

void add(int pos) {
	int x = id[pos];
	if (vis[x]) dv.del(tofa[x]);
	else dv.ins(tofa[x]);
	vis[x] = !vis[x];
}

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);

	std::cin >> n >> q;
	B = std::sqrt(2 * n);

	for (int i = 1; i < n; ++i) {
		int u, v, w;
		std::cin >> u >> v >> w;
		adj[u].push_back({v, w});
		adj[v].push_back({u, w});
	}

	dfs(1, 0);

	for (int j = 1; j <= std::__lg(n); ++j) {
		for (int i = 1; i + (1 << j) - 1 <= n; ++i) {
			st[i][j] = get(st[i][j - 1], st[i + (1 << j - 1)][j - 1]);
		}
	}

	for (int i = 1; i <= q; ++i) {
		int x, y;
		std::cin >> x >> y;
		if (f[x] > f[y]) std::swap(x, y);
		if (getlca(x, y) == x) b[i] = (Query) {f[x] + 1, f[y], i};
		else b[i] = (Query) {g[x], f[y], i};
	}

	for (int i = 1; i <= 2 * n; ++i) {
		bel[i] = (i - 1) / B + 1;
	}

	dv.init();

	std::sort(b + 1, b + 1 + q);

	// for (int i = 1; i <= tot; ++i) {
	// 	std::cout << id[i] << " \n"[i == tot];
	// }

	int l = 1, r = 0;
	for (int i = 1; i <= q; ++i) {
		// std::cerr << b[i].l << " " << b[i].r << "\n";
		while (l > b[i].l) add(--l);
		while (l < b[i].l) add(l++);
		while (r < b[i].r) add(++r);
		while (r > b[i].r) add(r--);
		// for (int j = 0; j <= n; ++j) {
		// 	std::cout << dv.pos[j] << " \n"[j == n];
		// }
		ans[b[i].idx] = dv.qry();
	}

	for (int i = 1; i <= q; ++i) {
		std::cout << ans[i] << "\n";
	}

	return 0;
}