#include <bits/stdc++.h>
#define re register
#define fst first
#define snd second
#define int long long
#define chmax(a,b) (a = max(a,(b)))

using namespace std;

typedef pair<int,int> pii;
const int N = 5e5 + 10;
int n,q,ans[N];
int tim,sz[N],dfn[N],pid[N],dep[N];
vector<pii> g1[N],g2[N],Q[N];

inline int read(){
    int r = 0,w = 1;
    char c = getchar();
    while (c < '0' || c > '9'){
        if (c == '-') w = -1;
        c = getchar();
    }
    while (c >= '0' && c <= '9'){
        r = (r << 3) + (r << 1) + (c ^ 48);
        c = getchar();
    }
    return r * w;
}

namespace LCA{
    #define pot(x) (1 << (x))

    const int M = 24;
    int tim,lg[N],dfn[N],dep[N],dp[N][M];

    inline void dfs(int u,int fa){
        dp[dfn[u] = ++tim][0] = dep[u];
        for (pii v:g2[u]){
            if (v.fst == fa) continue;
            dep[v.fst] = dep[u] + v.snd;
            dfs(v.fst,u);
        }
        dp[++tim][0] = dep[u];
    }

    inline void init(){
        dfs(1,0);
        for (re int i = 2;i <= tim;i++) lg[i] = lg[i >> 1] + 1;
        for (re int j = 1;j <= lg[tim];j++){
            for (re int i = 1;i + pot(j) - 1 <= tim;i++) dp[i][j] = min(dp[i][j - 1],dp[i + pot(j - 1)][j - 1]);
        }
    }

    inline int lca(int x,int y){
        int sx = dfn[x],sy = dfn[y];
        if (sx > sy) swap(sx,sy);
        int t = lg[sy - sx + 1];
        return min(dp[sx][t],dp[sy - pot(t) + 1][t]);
    }

    inline int dist(int x,int y){
        return (dep[x] + dep[y] - 2 * lca(x,y));
    }

    #undef pot
}
using LCA::dist;

struct{
    #define ls(u) (u << 1)
    #define rs(u) (u << 1 | 1)
    #define val(u) (tr[u].val)

    struct value{
        int a,b,vala,valb;

        bool friend operator <(const value &a,const value &b){
            #define calc(x) (x.a == x.b ? 0 : (dist(x.a,x.b) + x.vala + x.valb))
            return calc(a) < calc(b);
            #undef calc
        }

        value friend operator +(const value &a,const value &b){
            value res = max(a,b);
            chmax(res,((value){a.a,b.a,a.vala,b.vala}));
            chmax(res,((value){a.a,b.b,a.vala,b.valb}));
            chmax(res,((value){a.b,b.a,a.valb,b.vala}));
            chmax(res,((value){a.b,b.b,a.valb,b.valb}));
            return res;
        }
    };

    struct node{
        int l,r,tag;
        value val;
    }tr[N << 2];

    inline void calc(int u,int k){
        tr[u].tag += k;
        val(u).vala += k; val(u).valb += k;
    }

    inline void pushup(int u){
        val(u) = val(ls(u)) + val(rs(u));
    }

    inline void pushdown(int u){
        if (tr[u].tag){
            calc(ls(u),tr[u].tag); calc(rs(u),tr[u].tag);
            tr[u].tag = 0;
        }
    }

    inline void build(int u,int l,int r){
        tr[u] = {l,r};
        if (l == r) return (val(u) = {pid[l],pid[l],dep[pid[l]],dep[pid[l]]}),void();
        int mid = l + r >> 1;
        build(ls(u),l,mid); build(rs(u),mid + 1,r);
        pushup(u);
    }

    inline void modify(int u,int l,int r,int k){
        // cerr << u << " " << tr[u].l << " " << tr[u].r << " " << l << " " << r << " modify\n";
        if (l <= tr[u].l && tr[u].r <= r) return calc(u,k);
        pushdown(u);
        int mid = tr[u].l + tr[u].r >> 1;
        if (l <= mid) modify(ls(u),l,r,k);
        if (r > mid) modify(rs(u),l,r,k);
        pushup(u);
    }

    #undef ls
    #undef rs
    #undef val
}T;

inline void dfs1(int u,int fa){
    sz[u] = 1;
    pid[dfn[u] = ++tim] = u;
    for (pii v:g1[u]){
        if (v.fst == fa) continue;
        dep[v.fst] = dep[u] + v.snd;
        dfs1(v.fst,u); sz[u] += sz[v.fst];
    }
}

inline void dfs2(int u,int fa){
    auto val = T.tr[1].val;
    // cerr << u << " ????\n";
    for (pii p:Q[u]) ans[p.snd] = max(dist(p.fst,val.a) + val.vala,dist(p.fst,val.b) + val.valb);
    for (pii v:g1[u]){
        if (v.fst == fa) continue;
        T.modify(1,1,n,v.snd);
        // cerr << v.fst << " " << dfn[v.fst] << " " << sz[v.fst] << " sbsb\n";
        T.modify(1,dfn[v.fst],dfn[v.fst] + sz[v.fst] - 1,-2 * v.snd);
        dfs2(v.fst,u);
        T.modify(1,1,n,-v.snd);
        T.modify(1,dfn[v.fst],dfn[v.fst] + sz[v.fst] - 1,2 * v.snd);
    }
}

signed main(){
    n = read(),q = read();
    for (re int i = 1,a,b,c;i < n;i++){
        a = read(),b = read(),c = read();
        g1[a].push_back({b,c});
        g1[b].push_back({a,c});
    }
    for (re int i = 1,a,b,c;i < n;i++){
        a = read(),b = read(),c = read();
        g2[a].push_back({b,c});
        g2[b].push_back({a,c});
    }
    for (re int i = 1,x,y;i <= q;i++){
        x = read(),y = read();
        // cerr << x << " " << y << " ???\n";
        Q[x].push_back({y,i});
    }
    dfs1(1,0); LCA::init(); T.build(1,1,n); dfs2(1,0);
    // for (re int i = 1;i <= n;i++) cerr << dfn[i] << " "; cerr << "\n";
    // for (re int i = 1;i <= n;i++) cerr << sz[i] << " "; cerr << "\n";
    for (re int i = 1;i <= q;i++) printf("%lld\n",ans[i]);
    return 0;
}