#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
struct Tree {
// public:
    int n, s, root, tot;
    std::vector<int> fa, top, dfn, id, sz, son;
    std::vector<i64> dep;
    std::vector<std::vector<std::pair<int, int>>> adj;
    Tree() {Tree(0);}
    Tree(int _n) {
        init(_n, 0);
    }
    Tree(int _n, int rt) {
        init(_n, rt);
    }
    void init(int _n, int rt) {
        n = _n; tot = 0;
        dep.assign(n, 0);
        fa.assign(n, 0);
        top.assign(n, 0);
        dfn.assign(n, 0);
        id.assign(n, 0);
        sz.assign(n, 1);
        son.assign(n, -1);
        adj.assign(n, {});
        root = rt;
    }
    void add(int u, int v, int w = 1) {
        adj[u].push_back(std::pair(v, w));
        adj[v].push_back(std::pair(u, w));
    }
    void dfs(int x, int fath) {
    	// cerr << "CAO: " << adj.size() << ' ' << adj[x].size() << '\n';
    	// for (auto [v, w] : adj[x]) cerr << x <<' ' <<v << ' ' << w << '\n';
        for (auto [v, w] : adj[x])
            if (v != fath) {
                fa[v] = x;
                dep[v] = dep[x] + w;
                dfs(v, x);
                sz[x] += sz[v];
                if (son[x] == -1 || sz[son[x]] < sz[v])
                    son[x] = v;
            }
    }
    void dfs2(int x, int topf) {
        top[x] = topf;
        id[dfn[x] = tot++] = x;
        if (son[x] == -1) {
            return ;
        }
        dfs2(son[x], topf);
        for (auto [v, w] : adj[x]) {
            if (v == son[x] || v == fa[x])
                continue;
            dfs2(v, v);
        }
    }
    int lca(int u, int v) {
        while (top[u] != top[v]) {
            if (dep[top[u]] < dep[top[v]])
                std::swap(u, v);
            u = fa[top[u]];
        }
        return (dep[u] < dep[v] ? u : v);
    }
    i64 dist(int u, int v) {
        return dep[u] + dep[v] - 2 * dep[lca(u, v)];
    }
    bool isAcestor(int u, int v) {
        return lca(u, v) == u;
    }

    void init() {
    	// cerr << root << ' ' << root << "!\n";
        dfs(root, root);
        dfs2(root, root);
    }
} ;
template<class Info>
class SegmentTree {
public:
    int n;
    std::vector<Info> info;
    SegmentTree() : n{} {}
    SegmentTree(int _n) {
        Build(_n, std::vector<Info> (_n, {}));
    }
    SegmentTree(int _n, std::vector<Info> a) {
        Build(_n, a);
    }

    void Build(int _n, std::vector<Info> a) {
        n = _n;
        info.assign(n << 2, {});
        std::function<void(int, int, int)> build = [&](int x, int l, int r) {
            if (l + 1 == r) {
                info[x] = a[l];
                return ;
            }
            int mid = (l + r) >> 1;
            build(x << 1, l, mid);
            build(x << 1 | 1, mid, r);
            info[x] = info[x << 1] + info[x << 1 | 1];
        } ;
        build(1, 0, n);
    }

    void Modify(int x, int l, int r, int pos/*, Info val*/) {
        if (l + 1 == r) {
            // info[x] = val;
            return ;
        }
        int mid = (l + r) >> 1;
        if (pos < mid) {
            Modify(x << 1, l, mid, pos/*, val*/);
        } else {
            Modify(x << 1 | 1, mid, r, pos/*, val*/);
        }
        info[x] = info[x << 1] + info[x << 1 | 1];
    }
    void Modify(int pos/*, Info val*/) {
        Modify(1, 0, n, pos/*, val*/);
    }

    Info RangeQuery(int x, int l, int r, int L, int R) {
        if (l >= R || r <= L)
            return {};
        if (l >= L && r <= R)
            return info[x];
        int mid = (l + r) >> 1;
        return RangeQuery(x << 1, l, mid, L, R) + RangeQuery(x << 1 | 1, mid, r, L, R);
    }
    Info RangeQuery(int L, int R) {
        return RangeQuery(1, 0, n, L, R);
    }
    Info Query(int pos) {
        return RangeQuery(pos, pos + 1);
    }
} ;
struct Info {
	int l = 0, r = 0;
} ;
Tree A, B;
int now;
i64 getdis(int x, int y) {
	return A.dist(now, x) + A.dist(now, y) + B.dist(x, y);
}
Info operator + (Info lhs, Info rhs) {
	Info res = lhs; i64 R = getdis(lhs.l, lhs.r);
	vector<int> vec = {lhs.l, lhs.r, rhs.l, rhs.r};
	for (int i = 0; i < 4; ++i) for (int j = i + 1; j < 4; ++j) {
		if (getdis(vec[i], vec[j]) > R) {
			R = getdis(vec[i], vec[j]);
			res.l = vec[i], res.r = vec[j];
		}
	}
    return res;
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n, q; cin >> n >> q;
	A.init(n, 0); B.init(n, 0);
	vector<vector<array<int, 2>>> vec(n), t1(n);
	vector<i64> ans(q);
	for (int i = 1; i < n; ++i) {
		int u, v, w; cin >> u >> v >> w; --u, --v;
		A.add(u, v, w);
		t1[u].push_back({v, w});
		t1[v].push_back({u, w});
    }
	for (int i = 1; i < n; ++i) {
		int u, v, w; cin >> u >> v >> w, --u, --v;
		B.add(u, v, w);
	} 
	A.init(); 
	B.init();
	for (int i = 0; i < q; ++i) {
		int a, b; cin >> a >> b, --a, --b;
		vec[a].push_back({b, i});
	}
	vector<Info> init(n);
	for (int i = 0; i < n; ++i) init[i].l = init[i].r = A.id[i];
	SegmentTree<Info> seg(n, init);
	auto upd = [&](int x, int type) {
		if (type == 0) now = x;
		else now = A.fa[x];
		seg.Modify(A.dfn[now]); seg.Modify(A.dfn[now] + A.sz[now] - 1);
	} ;
	function<void(int, int)> dfs = [&](int x, int fa) {
		if (x > 0) upd(x, 0);
		int l = seg.RangeQuery(0, n).l, r = seg.RangeQuery(0, n).r;
        // cerr << x << ' ' << l << ' '<< r << "cao\n";
		for (auto [v, i] : vec[x]) {
			i64 vx = A.dist(l, x) + B.dist(l, v);
			i64 vy = A.dist(r, x) + B.dist(r, v);
			ans[i] = max(vx, vy);
		}
		for (auto [v, w] : t1[x]) if (v != fa) dfs(v, x);
		if (x > 0) upd(x, 1);
	} ;
	dfs(0, 0);
	for (int i = 0; i < q; ++i) cout << ans[i] << '\n';
}