#include <bits/stdc++.h>
#ifdef LOCAL
#include "cp_debug.h"
#else
#define debug(...) 42
#endif
#define int long long
#define rep(i,a,b) for(int i = a; i < b; ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;

template<typename T> void read(T &x){
    x = 0;char ch = getchar();ll f = 1;
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
    while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
template<typename T, typename... Args> void read(T &first, Args& ... args) {
    read(first);
    read(args...);
}
template<typename T> void write(T x) {
    if(x > 9) write(x/10);
    putchar(x%10 + '0');
}

const int N = 2030, INF = 0x3f3f3f3f3f3f3f3f;
vector<pii> G[N];

signed main() {
    int n, q;
    read(n, q);
    ll lsum = 0;
    rep(i,1,n) {
        int u, v, w;
        read(u, v, w);
        G[u].emplace_back(v, w);
        G[v].emplace_back(u, w);
        lsum += w;
    }
    while(q--) {
        int start, key, trap;
        read(start, key, trap);

        vi fath(n+1), depth(n+1), dist(n+1);
        function<void(int,int,int,int)> dfs = [&](int u, int fa, int dep, int dis) {
            fath[u] = fa;
            depth[u] = dep;
            dist[u] = dis;
            for(auto [v, w]: G[u]) if(v != fa) {
                dfs(v, u, dep+1, dis+w);
            }
        };
        dfs(start, -1, 0, 0);

        auto lca = [&](int u, int v) {
            while(u != v) {
                if(depth[u] > depth[v]) u = fath[u];
                else if(depth[v] > depth[u]) v = fath[v];
                else { u = fath[u], v = fath[v]; }
            }
            return u;
        };

        int lca_key_trap = lca(key, trap);
        if(lca_key_trap == trap) {
            cout<<"impossible\n";
            continue;
        }
        debug(lca_key_trap,key,trap,lsum);
        if(lca_key_trap == key) {
            debug("lca = key",lca_key_trap,key,trap);
            cout<<lsum*2-*max_element(dist.begin()+1, dist.end())<<'\n';
            continue;
        }

        vi marked(n+1), is_key_parent(n+1), top(n+1);
        int key_subtree = key;
        is_key_parent[key] = true;
        while(fath[key_subtree] != lca_key_trap) {
            key_subtree = fath[key_subtree];
            is_key_parent[key_subtree] = 1;
        }

        function<void(int,int,int)> dfs2 = [&](int u, int fa, int tp) {
            marked[u] = true;
            top[u] = tp;
            for(auto [v, w]: G[u]) if(v != fa) {
                dfs2(v, u, is_key_parent[v] ? v : tp);
            }
        };
        debug(is_key_parent);
        debug(dist,key_subtree);
        dfs2(key_subtree, lca_key_trap, key_subtree);
        debug(marked);
        int ans = INF;
        rep(i,1,n+1) {
            if(marked[i]) {
                debug(i,top[i],dist[i],dist[top[i]],lsum*2+dist[top[i]]-dist[lca_key_trap]-dist[i]);
                ans = min(ans, lsum*2+dist[top[i]]-dist[lca_key_trap]-dist[i]);
            } else {
                ans = min(ans, lsum*2-dist[i]);
            }
        }
        cout<<ans<<'\n';
    }
    return 0;
}