/*
  ....
  .##.
  .##.
H.AKLESS
# #### #
# #### #
# #### #
# #### #
 ##  ##
 ##  ##
 ##  ##
*/
#include <bits/stdc++.h>
#define st first
#define nd second
#define db double
#define re register
#define pb push_back
#define mk make_pair
#define int long long
#define ldb long double
#define pii pair<int, int>
#define ull unsigned long long 
#define mst(a, b) memset(a, b, sizeof(a))
using namespace std;
const int N = 1e5 + 10, M = 5e5 + 10;
inline int read()
{
  int s = 0, w = 1;
  char ch = getchar();
  while(ch < '0' || ch > '9') { if(ch == '-') w *= -1; ch = getchar(); }
  while(ch >= '0' && ch <= '9') s = s * 10 + ch - '0', ch = getchar();
  return s * w;
}
struct edge{ int v, w; };
struct Que{ int x, id; };
int n, Q, tim, ans[M];
int id[N], out[N], dfn[N], init[N];
int up[N], dep[N], dis[N], siz[N], son[N], top[N];
vector<Que> q[N];
vector<edge> G[2][N];
inline void Pre(int u, int fa) 
{
	up[u] = fa, siz[u] = 1, dep[u] = dep[fa] + 1;
	for(re edge to : G[1][u]){
		if(to.v == fa) continue;
		dis[to.v] = dis[u] + to.w;
		Pre(to.v, u), siz[u] += siz[to.v];
		if(siz[to.v] > siz[son[u]]) son[u] = to.v; 
	}
}
inline void DFS(int u, int fa, int tp)
{
	top[u] = tp;
	if(son[u]) DFS(son[u], u, tp);
	for(re edge to : G[1][u])
		if(to.v != fa && to.v != son[u]) DFS(to.v, u, to.v);
}
inline int LCA(int x, int y)
{
	while(top[x] != top[y]){
		if(dep[top[x]] < dep[top[y]]) swap(x, y);
		x = up[top[x]];
	}
	return dep[x] < dep[y] ? x : y;
}
inline int dist(int x, int y) { return dis[x] + dis[y] - 2 * dis[LCA(x, y)]; }
inline void Run(int u, int fa)
{
	dfn[u] = ++tim, id[tim] = u;
	for(re edge to : G[0][u])
		if(to.v != fa) init[to.v] = init[u] + to.w, Run(to.v, u);
	out[u] = tim;
}
#define ls k << 1
#define rs k << 1 | 1
#define mid ((l + r) >> 1)
struct SegmentTree{ 
	int tr[N << 2][2], tag[N << 2]; //修改标记 
	inline int ask(int k, int l, int r, int x){
		if(l == r && l == x) return tag[k];
		if(x <= mid) return tag[k] + ask(ls, l, mid, x);
		else return tag[k] + ask(rs, mid + 1, r, x);
	}
	inline void pushup(int k){
		int mx = 0, pos[4] = {tr[ls][0], tr[ls][1], tr[rs][0], tr[rs][1]};
		for(re int i = 0; i < 4; i++){
			for(re int j = i + 1; j < 4; j++){
				int x = pos[i], y = pos[j], v = dist(x, y) + ask(1, 1, n, x) + ask(1, 1, n, y);
				if(v > mx) mx = v, tr[k][0] = x, tr[k][1] = y;
			}
		}
	}
	inline void build(int k, int l, int r){
		if(l == r) { tag[k] = init[id[l]], tr[k][0] = tr[k][1] = id[l]; return; }
		build(ls, l, mid), build(rs, mid + 1, r);
		pushup(k);
	}
	inline void update(int k, int l, int r, int x, int y, int v){
		if(x > y) return;
		if(l >= x && r <= y) { tag[k] += v; return; } 
		if(y <= mid) update(ls, l, mid, x, y, v);
		else if(x > mid) update(rs, mid + 1, r, x, y, v);
		else update(ls, l, mid, x, mid, v), update(rs, mid + 1, r, mid + 1, y, v);
		pushup(k);
	}
}T;
inline void Sol(int u, int fa)
{
	int x = T.tr[1][0], y = T.tr[1][1]; //直径的两个端点 
	for(re Que it : q[u]) ans[it.id] = max(T.ask(1, 1, n, x) + dist(it.x, x), T.ask(1, 1, n, y) + dist(it.x, y));
	for(re edge to : G[0][u]){
		if(to.v == fa) continue;
		T.update(1, 1, n, dfn[to.v], out[to.v], -to.w);
		T.update(1, 1, n, 1, dfn[to.v] - 1, to.w), T.update(1, 1, n, out[to.v] + 1, n, to.w);
		Sol(to.v, u);
		T.update(1, 1, n, dfn[to.v], out[to.v], to.w);
		T.update(1, 1, n, 1, dfn[to.v] - 1, -to.w), T.update(1, 1, n, out[to.v] + 1, n, -to.w);
	}
}
signed main()
{
	n = read(), Q = read();
	for(re int i = 1, x, y, z; i < n; i++)
		x = read(), y = read(), z = read(), G[0][x].pb((edge){y, z}), G[0][y].pb((edge){x, z});
	for(re int i = 1, x, y, z; i < n; i++)
		x = read(), y = read(), z = read(), G[1][x].pb((edge){y, z}), G[1][y].pb((edge){x, z});
	for(re int i = 1, x, y; i <= Q; i++) x = read(), y = read(), q[x].pb((Que){y, i});
	Pre(1, 0), DFS(1, 0, 1), Run(1, 0);
	T.build(1, 1, n);
	Sol(1, 0);
	for(re int i = 1; i <= Q; i++) printf("%lld\n", ans[i]);
	return 0;
}
/*
1
5
1 5
2 5
2 7
3 3
4 10
*/