#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
#include<array>
#include<chrono>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 998244353;
//constexpr ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;

#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;

template<typename T>
void chmin(T& a, T b) {
	a = min(a, b);
}
template<typename T>
void chmax(T& a, T b) {
	a = max(a, b);
}
template<typename T>
void cinarray(vector<T>& v) {
	rep(i, v.size())cin >> v[i];
}
template<typename T>
void coutarray(vector<T>& v) {
	rep(i, v.size()) {
		if (i > 0)cout << " "; cout << v[i];
	}
	cout << "\n";
}
ll mod_pow(ll x, ll n, ll m = mod) {
	if (n < 0) {
		ll res = mod_pow(x, -n, m);
		return mod_pow(res, m - 2, m);
	}
	if (abs(x) >= m)x %= m;
	if (x < 0)x += m;
	//if (x == 0)return 0;
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
//mod should be <2^31
struct modint {
	int n;
	modint() :n(0) { ; }
	modint(ll m) {
		if (m < 0 || mod <= m) {
			m %= mod; if (m < 0)m += mod;
		}
		n = m;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
bool operator<(modint a, modint b) { return a.n < b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= (int)mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += (int)mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
modint operator/=(modint& a, modint b) { a = a / b; return a; }
const int max_n = 1 << 20;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
modint combP(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[a - b];
}

ll gcd(ll a, ll b) {
	a = abs(a); b = abs(b);
	if (a < b)swap(a, b);
	while (b) {
		ll r = a % b; a = b; b = r;
	}
	return a;
}
using ld = double;
//typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-10;
const ld pi = acosl(-1.0);
template<typename T>
void addv(vector<T>& v, int loc, T val) {
	if (loc >= v.size())v.resize(loc + 1, 0);
	v[loc] += val;
}
/*const int mn = 2000005;
bool isp[mn];
vector<int> ps;
void init() {
	fill(isp + 2, isp + mn, true);
	for (int i = 2; i < mn; i++) {
		if (!isp[i])continue;
		ps.push_back(i);
		for (int j = 2 * i; j < mn; j += i) {
			isp[j] = false;
		}
	}
}*/

//[,val)
template<typename T>
auto prev_itr(set<T>& st, T val) {
	auto res = st.lower_bound(val);
	if (res == st.begin())return st.end();
	res--; return res;
}

//[val,)
template<typename T>
auto next_itr(set<T>& st, T val) {
	auto res = st.lower_bound(val);
	return res;
}
using mP = pair<modint, modint>;
mP operator+(mP a, mP b) {
	return { a.first + b.first,a.second + b.second };
}
mP operator+=(mP& a, mP b) {
	a = a + b; return a;
}
mP operator-(mP a, mP b) {
	return { a.first - b.first,a.second - b.second };
}
mP operator-=(mP& a, mP b) {
	a = a - b; return a;
}
LP operator+(LP a, LP b) {
	return { a.first + b.first,a.second + b.second };
}
LP operator+=(LP& a, LP b) {
	a = a + b; return a;
}
LP operator-(LP a, LP b) {
	return { a.first - b.first,a.second - b.second };
}
LP operator-=(LP& a, LP b) {
	a = a - b; return a;
}

mt19937 mt(time(0));

const string drul = "DRUL";
string senw = "SENW";
//DRUL,or SENW
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
//-----------------------------------------

//verified with https://yukicoder.me/problems/no/1197
//O(NlogN)



struct edge {
	int to;
	ll cost;
};
struct pdata {
	int g, id;
	ll dist;
};
struct Centroid_Decomposition {
private:
	int n;
	vector<vector<edge>> G;


public:
	vector<vector<pdata>> vpd;
	vector<vector<int>> fG; int root;
	vector<vector<P>> oriv;
	vector<vector<ll>> orid;
	Centroid_Decomposition(int n_) {
		n = n_;
		G.resize(n);

		fG.resize(n); root = -1;
		vpd.resize(n);
		oriv.resize(n);
		orid.resize(n);
	}
	void add_edge(int a, int b, int c) {
		G[a].push_back({ b,c });
		G[b].push_back({ a,c });
	}

	void complete() {
		vector<int> exi(n, 0);
		vector<int> ori(n); rep(i, n)ori[i] = i;


		int tmp = 0;
		function<int(int, int, int&, int&)> szdfs = [&](int id, int fr, int& g, int& sz)->int {
			int res = 1;
			int ma = 0;
			for (edge e : G[id]) {
				if (tmp != exi[e.to])continue;
				if (e.to == fr)continue;
				int nex = szdfs(e.to, id, g, sz);
				ma = max(ma, nex);
				res += nex;
			}
			if (ma <= sz / 2 && sz - res <= sz / 2)g = id;
			return res;
		};

		function<int(vector<int>)> cdfs = [&](vector<int> v)->int {
			tmp++;
			if (v.empty())return 0;

			for (int id : v) {
				exi[id]++;
			}
			int g;
			int sz = v.size();
			szdfs(v[0], -1, g, sz);

			oriv[g].push_back({ g,-1 });
			orid[g].push_back(0);

			int ctmp = 0;
			for (edge e : G[g]) {
				if (!exi[e.to])continue;
				if (exi[e.to] != tmp)continue;
				vector<int> nex;
				function<void(int, int, ll)> dfs = [&](int id, int fr, ll d) {
					nex.push_back(id);
					vpd[id].push_back({ g,ctmp,d });
					oriv[g].push_back({ id,ctmp });
					orid[g].push_back(d);
					for (edge e : G[id]) {
						if (e.to == fr)continue;
						if (exi[e.to] != tmp)continue;
						dfs(e.to, id, d + e.cost);
					}
				};
				dfs(e.to, g, e.cost);


				int ng = cdfs(nex);
				fG[g].push_back(ng);
				ctmp++;
			}

			for (int id : v) {
				exi[id]--;
			}
			tmp--;
			return g;
		};
		root = cdfs(ori);

	}

};

using ar = array<ll, 3>;
/*
bool canadd(vector<ar>& v, ar& a) {
	if (v.empty())return true;
	rep(i, v.size()) {
		if (v[i][1] == a[1] && v[i][2] == a[2])return false;
	}
	bool s[2] = { true,true };
	rep1(i, v.size() - 1) {
		rep1(j, 2) {
			if (v[i][j] != v[0][j]) {
				s[j-1] = false;
			}
		}
	}
	if (s[0] && s[1]) {
		//assert(v.size()==1);
		return true;
	}
	else if (s[0]||s[1]) {
		int id = 0;
		if (s[1])id = 1;
		return v[0][id + 1] != a[id + 1];
	}
	else {

	}
	int c1[2] = {};
	{
		rep1(j, 2) {
			if (v[i][j] == a[j])c1[j - 1]++;
		}
	}
	rep(j, 2)if (c1[j] == 0 && s[j])return true;

}*/

struct ste {
	int lev;
	int x, y;
	vector<P> cp;
	ste() {
		lev = 0;
	}
};
bool add(ste& s, ar a) {
	if (s.lev == 0) {
		s.lev = 1;
		s.x = a[1]; s.y = a[2];
		return true;
	}
	else if (s.lev == 1) {
		if (s.x == a[1] && s.y == a[2])return false;
		if (s.x == a[1]) {
			s.lev = 2; return true;
		}
		else if (s.y == a[2]) {
			s.lev = 3; return true;
		}
		else {
			s.lev = 4;
			s.cp.push_back({ s.x,a[2] });
			s.cp.push_back({ a[1],s.y });
			return true;
		}
	}
	else if (s.lev == 2) {
		if (s.x == a[1])return false;
		s.lev = 4;
		s.cp.push_back({ s.x,a[2] });
		return true;
	}
	else if (s.lev == 3) {
		if (s.y == a[2])return false;
		s.lev = 4;
		s.cp.push_back({ a[1],s.y });
		return true;
	}
	else {
		vector<P> ncp;
		rep(i, s.cp.size()) {
			if (s.cp[i].first == a[1] || s.cp[i].second == a[2])ncp.push_back(s.cp[i]);
		}
		swap(s.cp, ncp);
		return s.cp.size() == ncp.size();
	}
}
void upd(vector<ar>& v, ar& a) {
	int chk = v.size();
	rep(i, v.size()) {
		if (v[i][0] <= a[0]) {
			chk = i; break;
		}
	}
	vector<ar> res;
	ste s;
	rep(i, chk) {
		if (add(s, v[i]))res.push_back(v[i]);
	}
	if (add(s, a))res.push_back(a);
	Rep(i, chk, v.size()) {
		if (add(s, v[i]))res.push_back(v[i]);
	}
	swap(v, res);
}
ll query(vector<ar>& v, int c0, int c1) {
	rep(i, v.size()) {
		if (v[i][1] != c0 && v[i][2] != c1)return v[i][0];
	}
	return -INF;
}

void solve() {
	int n, q; cin >> n >> q;
	Centroid_Decomposition G(n), H(n);
	rep(i, n - 1) {
		int a, b, c; cin >> a >> b >> c; a--; b--;
		G.add_edge(a, b, c);
	}
	rep(i, n - 1) {
		int a, b, c; cin >> a >> b >> c; a--; b--;
		H.add_edge(a, b, c);
	}
	G.complete();
	H.complete();
	vector<int> qa(q), qb(q);
	rep(i, q) {
		cin >> qa[i] >> qb[i];
		qa[i]--; qb[i]--;
	}
	vector<vector<int>>qs(n);
	rep(i, q)qs[qb[i]].push_back(i);
	auto& fG = H.fG;
	auto& oriv = H.oriv;
	auto& orid = H.orid;
	vector<vector<ar>> mem(n);
	auto addmem = [&](int id, int col, ll d) {
		ar nw;
		nw = { d,-1,col };
		upd(mem[id], nw);
		for (auto pre : G.vpd[id]) {
			int g = pre.g;
			int c = pre.id;
			ll nd = d + pre.dist;
			nw = { nd,c,col };
			upd(mem[g], nw);
		}
	};
	auto ermem = [&](int id) {
		mem[id].clear();
		for (auto pre : G.vpd[id]) {
			mem[pre.g].clear();
		}
	};
	auto memquery = [&](int id, int col) {
		ll res = -INF;
		chmax(res, query(mem[id], -2, col));
		for (auto pre : G.vpd[id]) {
			int g = pre.g;
			int c = pre.id;
			chmax(res, query(mem[g], c, col) + pre.dist);
		}
		return res;
	};
	vector<ll> ans(q, 0);
	rep(i, n) {
		rep(j, oriv[i].size()) {
			int id = oriv[i][j].first;
			int col = oriv[i][j].second;
			ll d = orid[i][j];
			addmem(id, col, d);
		}
		rep(j, oriv[i].size()) {
			int id = oriv[i][j].first;
			int col = oriv[i][j].second;
			if (col < 0)col--;
			for (auto qid : qs[id]) {
				ll val = memquery(qa[qid], col);
				val += orid[i][j];
				//cout << "?? " << val << "\n";
				chmax(ans[qid], val);
			}
		}
		rep(j, oriv[i].size()) {
			int id = oriv[i][j].first;
			ermem(id);
		}
	}
	rep(i, q)cout << ans[i] << "\n";
}


signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(10);
	//init_f();
	//init();
	//expr();
	//while(true)
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}