#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
const int N = 2E5 + 5, M = 5E5 + 5;
int n, q, m;
vector<array<int, 2>> vec[N], adj[N];
int head[N], nex[N << 1], to[N << 1], from[N << 1], dis[N << 1], tot = 1;
i64 Ans[M];
void ad(int x, int y, int z) {
	to[++tot] = y; dis[tot] = z; from[tot] = x;
	nex[tot] = head[x]; head[x] = tot;
}
void add(int x, int y, int z) {
	ad(x, y, z); ad(y, x, z);
}
void rebuild(int x, int fa) {
	int temp = 0, len = (int)adj[x].size(), last;
	for (auto [v, w] : adj[x]) if (v != fa) {
		++temp; if (temp == 1) {	
			add(x, v, w);
			last = x;
		} else if (temp == len - (x != 1)) {
			add(last, v, w);
		} else {
			++m; add(last, m, 0);
			last = m; add(m, v, w);
		}
	}
	for (auto [v, w] : adj[x]) if (v != fa) rebuild(v, x);
}
i64 d1[N];
const int K = 20;
struct VirtualTree {
	vector<array<int, 2>> adj[N];
	void add(int x, int y, int z) {
		adj[x].push_back({y, z});
		adj[y].push_back({x, z});
	}
	int st[N][K], dfn[N], tot;
	i64 dep[N];
	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;
		for (auto [v, w] : adj[x]) if (v != fa) {dep[v] = dep[x] + w; dfs(v, x);}
	}
	int getlca(int u, int v) {
		if (u == v) return u;
		if ((u = dfn[u]) > (v = dfn[v])) swap(u, v);
		int d = __lg(v - u++);
		return get(st[u][d], st[v - (1 << d) + 1][d]);
	}
	void init() {
		dfs(1, 0);
		for (int j = 1; j <= __lg(n * 2); ++j)
			for (int i = 1; i + (1 << j) - 1 <= 2 * n; ++i)
				st[i][j] = get(st[i][j - 1], st[i + (1 << j - 1)][j - 1]);
		
	}
	i64 dist(int x, int y) {
		i64 val = 0;
		if (x > n) val += d1[x - n];
		if (y > n) val += d1[y - n];
		return val + dep[x] + dep[y] - 2 * dep[getlca(x, y)];
	}
	vector<array<i64, 2>> e[N];
	void conn(int x, int y, i64 w) {
		// cerr << "connect: " << x << ' ' << y << ' ' << w << '\n';
		e[x].push_back({y, w});
		e[y].push_back({x, w});
	}
	vector<int> id;
	void build(vector<int> &h) {
		sort(h.begin(), h.end(), [&](int x, int y) {return dfn[x] < dfn[y];});
		vector<int> a = h; int len = h.size();
		for (int i = 0; i + 1 < len; ++i) a.push_back(getlca(h[i], h[i + 1]));
		sort(a.begin(), a.end(), [&](int x, int y) {return dfn[x] < dfn[y];});
		a.erase(unique(a.begin(), a.end()), a.end());
		// cerr << "A: "; for (auto x : a) cerr << x << ' '; cerr << '\n';
		len = a.size();
		for (int i = 0; i + 1 < len; ++i) {
			int lca = getlca(a[i], a[i + 1]);
			conn(lca, a[i + 1], dist(lca, a[i + 1]));
		} id = a;
	}
	bool vis[N]; i64 dis[2][N];
	int dot1, dot2;
	void getdiameter() {
		int t = id[0];
		auto bfs = [&](int st, i64 *dis) {
			for (auto x : id) vis[x] = 0;
			queue<int> q; q.push(st); dis[st] = 0; vis[st] = 1;
			while (!q.empty()) {
				int u = q.front(); q.pop();
				for (auto [v, w] : e[u]) {
					if (!vis[v]) {
						dis[v] = dis[u] + w;
						vis[v] = 1;
						q.push(v);
					}
				}
			}
		} ;
		bfs(t, dis[0]);
		int s = t;
		for (auto x : id) if (dis[0][x] > dis[0][s]) s = x;
		bfs(t = s, dis[0]);
		for (auto x : id) if (dis[1][x] > dis[1][t]) t = x;
		bfs(t, dis[1]);
		dot1 = s, dot2 = t;
		// cerr << "Diameter: " << dot1 << ' ' << dot2 << '\n';
	}
	i64 query(int x) {
		return max(dist(x, dot1), dist(x, dot2));
	}
	void clear() {
		for (auto x : id) dis[0][x] = dis[1][x] = 0;
		dot1 = dot2 = 0;
		id.clear();
	}
} f;
int dsum;
int rt, dmx, sz[N];
bool vis[N << 1];
void getroot(int x, int fa) {
	sz[x] = 1;
	for (int i = head[x]; i; i = nex[i]) {
		int v = to[i];
		if (v == fa || vis[i >> 1]) continue;
		getroot(v, x); sz[x] += sz[v];
		int temp = max(sz[v], dsum - sz[v]);
		if (dmx > temp) {
			dmx = temp;
			rt = i;
		}
	}
}
vector<int> dots;
void dfs(int x, int fa) {
	if (x <= n) dots.push_back(x + n);
	for(int i = head[x]; i; i = nex[i]) {
		int v = to[i];
		if (v == fa || vis[i >> 1]) continue;
		d1[v] = d1[x] + dis[i];
		dfs(v, x);
	}
}
void calc(int x, int fa, i64 dep) {
	if (x <= n) for (auto [b, i] : vec[x]) {
		// cerr << x << ' ' << fa << ' ' << dep << ' ' << b << ' ' << f.query(b) << " query\n";
		Ans[i] = max(Ans[i], f.query(b) + dep);
	}
	for (int i = head[x]; i; i = nex[i]) {
		int v = to[i];
		if (vis[i >> 1] || v == fa) continue;
		calc(v, x, dep + dis[i]);
	}
}
void work(int u, int v, int w) {
	// cerr << u << ' ' << v << ' ' << w << " !\n";
	d1[u] = w; dfs(u, v); f.build(dots);
	f.getdiameter(); calc(v, u, 0); dots.clear(); f.clear();
}
void solve(int x, int nsum) {
	rt = 0; dmx = 1E9; dsum = nsum;
	getroot(x, 0); if (!rt) return ;
	vis[rt / 2] = 1;
	int u = from[rt], v = to[rt], w = dis[rt];
	work(u, v, w); work(v, u, w);
	solve(u, nsum - sz[u]); solve(v, sz[v]);
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin >> n >> q;
	for (int i = 1; i < n; ++i) {
		int u, v, w; cin >> u >> v >> w;
		adj[u].push_back({v, w}); adj[v].push_back({u, w});
	}
	for (int i = 1; i < n; ++i) {
		int u, v, w; cin >> u >> v >> w;
		f.add(u, v, w);
	}
	for (int i = 1; i <= n; ++i) f.add(i, i + n, 0);
	f.init();
	for (int i = 1; i <= q; ++i) {
		int a, b; cin >> a >> b;
		vec[a].push_back({b, i});
	}
	m = n;
	rebuild(1, 0);
	solve(1, n);
	for (int i = 1; i <= q; ++i) cout << Ans[i] << '\n';
}