#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("mmx,avx2,sse2")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2005;
const ll LLINF = 0x3f3f3f3f3f3f3f3f;
 
vector <pair <int,int> > G[N];
int n,Q;
 
int dfc = 0,dfn[N][N],siz[N][N],dep2[N][N];
ll dep[N][N];
short mi[N][13][N],LOG[N];
void init_dfs(int u,int f,int rt){
    dfn[rt][u] = ++ dfc;
    mi[rt][0][dfn[rt][u]] = f;
    siz[rt][u] = 1;
    dep2[rt][u] = dep2[rt][f] + 1;
    for(auto [v,w] : G[u]){
        if(v == f) continue;
        dep[rt][v] = dep[rt][u] + w;
        init_dfs(v,u,rt);
        siz[rt][u] += siz[rt][v];
    }
}
 
ll sumw2 = 0;

int get_lca(int u,int v,int s){
    if(u == v) return u;
    if(dfn[s][u] > dfn[s][v]) swap(u,v);
    u = dfn[s][u]; v = dfn[s][v];
    int d = LOG[v - u++];
    return dep2[s][mi[s][d][u]] < dep2[s][mi[s][d][v - (1 << d) + 1]] ? mi[s][d][u] : mi[s][d][v - (1 << d) + 1];
}
 
void solve(){
    cin >> n >> Q;
    for(int u,v,w,i = 1;i < n;i ++){
        cin >> u >> v >> w;
        // u = 1; v = i + 1; w = 1000000000;
        G[u].push_back({v,w});
        G[v].push_back({u,w});
        sumw2 += 2ll * w;
    }
    
    LOG[0] = -1; for(int i = 1;i <= n;i ++) LOG[i] = LOG[i >> 1] + 1;
    for(int s = 1;s <= n;s ++){
        dep[s][s] = dep2[s][s] = 0; dfc = 0;
        init_dfs(s,0,s);
        for(int i = 1;i <= LOG[n];i ++){
            for(int j = 1;j + (1 << (i - 1)) <= n;j ++){
                mi[s][i][j] = dep2[s][mi[s][i - 1][j]] < dep2[s][mi[s][i - 1][j + (1 << (i - 1))]] ? mi[s][i - 1][j] : mi[s][i - 1][j + (1 << (i - 1))];
            }
        }
    }
    vector <int> lef;
    for(int i = 1;i <= n;i ++){
        if(G[i].size() == 1) lef.push_back(i);
    }

    for(int s,k,t,i = 1;i <= Q;i ++){
        cin >> s >> k >> t;
        // s = 1; k = 2; t = 3;
        ll ans = LLINF;
        for(int u : lef){
            if(u != s){
                ll dk = dep[s][get_lca(u,k,s)];
                ll dt = dep[s][get_lca(u,t,s)];
                ans = min(ans,sumw2 - dep[s][u] + 2 * max(0ll,dk - dt));
                // cout << u << ' ' << get_lca(u,k,s) << ' ' << dk << ' ' << dt << ' ' << ans << endl;
            }
        }
        if(dfn[s][t] <= dfn[s][k] && dfn[s][k] <= dfn[s][t] + siz[s][t] - 1) cout << "impossible\n";
        else cout << ans << '\n';
    }
}
 
int main(){
    ios::sync_with_stdio(false); cin.tie(0);
    solve();
    return 0;
}