#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 4005;
const ll LLINF = 0x3f3f3f3f3f3f3f3f;
 
vector <pair <int,int> > G[N];
int n,Q;
 
int dfc = 0,dfn[N],siz[N];
ll dep[N];
void init_dfs(int u,int f){
    dfn[u] = ++ dfc;
    siz[u] = 1;
    for(auto [v,w] : G[u]){
        if(v == f) continue;
        dep[v] = dep[u] + w;
        init_dfs(v,u);
        siz[u] += siz[v];
    }
}
 
int k,t;
ll dt,dk;
ll ans,sumw2 = 0;
void dfs(int u,int f,int dt,int dk){
    if(dfn[u] <= dfn[t] && dfn[t] <= dfn[u] + siz[u] - 1) dt = dep[u];
    if(dfn[u] <= dfn[k] && dfn[k] <= dfn[u] + siz[u] - 1) dk = dep[u];
    int is_leaf = 1;
    for(auto [v,w] : G[u]){
        if(v == f) continue;
        dfs(v,u,dt,dk);
        is_leaf = 0;
    }
    if(is_leaf){
        ans = min(ans,sumw2 - dep[u] + 2 * max(0ll,dk - dt));
    }
}
 
void solve(){
    cin >> n >> Q;
    for(int u,v,w,i = 1;i < n;i ++){
        cin >> u >> v >> w;
        G[u].push_back({v,w});
        G[v].push_back({u,w});
        sumw2 += 2ll * w;
    }
    for(int s,i = 1;i <= Q;i ++){
        cin >> s >> k >> t;
        dfc = 0; dep[s] = 0;
        init_dfs(s,0);
        ans = LLINF;
        dfs(s,0,1,1);
        if(dfn[t] <= dfn[k] && dfn[k] <= dfn[t] + siz[t] - 1) cout << "impossible\n";
        else cout << ans << '\n';
    }
}
 
int main(){
    ios::sync_with_stdio(false);
    solve();
    return 0;
}

answer.code: In function ‘void dfs(int, int, int, int)’:
answer.code:36:47: error: no matching function for call to ‘max(long long int, int)’
   36 |         ans = min(ans,sumw2 - dep[u] + 2 * max(0ll,dk - dt));
      |                                            ~~~^~~~~~~~~~~~~
In file included from /usr/include/c++/13/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:51,
                 from answer.code:1:
/usr/include/c++/13/bits/stl_algobase.h:257:5: note: candidate: ‘template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)’
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/13/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
answer.code:36:47: note:   deduced conflicting types for parameter ‘const _Tp’ (‘long long int’ and ‘int’)
   36 |         ans = min(ans,sumw2 - dep[u] + 2 * max(0ll,dk - dt));
      |                                            ~~~^~~~~~~~~~~~~
/usr/include/c++/13/bits/stl_algobase.h:303:5: note: candidate: ‘template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)’
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/13/bits/stl_algobase.h:303:5: note:   template argument deduction/substitution failed:
answer.code:36:47: note:   deduced conflicting types for parameter ‘const _Tp’ (‘long long int’ and ‘int’)
   36 |         ans = min(ans,sumw2 - dep[u] + 2 * max(0ll,dk - dt));
      |                                            ~~~^~~~~~~~~~~~~
In file included from /usr/include/c++/13/algorithm:61:
/usr/include/c++/13/bits/stl_algo.h:5795:5: note: candidate: ‘template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)’
 5795 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/13/bits/stl_algo.h:5795:5: note:   template argument deduction/substitution failed:
answer.code:36:47: note:   mismatched types ‘std::initializer_list<_Tp>’ and ‘long long int’
   36 |         ans = min(ans,sumw2 - dep[u] + 2 * max(0ll,dk - dt));
      |                                            ~~~^~~~~~~~~~~~~
/usr/include/c++/13/bits/stl_algo.h:5805:5: note: candidate: ‘template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)’
 5805 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/13/bits/stl_algo.h:5805:5: note:   template argument deduction/substitution failed:
answer.code:36:47: note:   mismatched types ‘std::initializer_list<_Tp>’ and ‘long long int’
   36 |         ans = min(ans,sumw2 - dep[u] + 2 * max(0ll,dk - dt));
      |                                            ~~~^~~~~~~~~~~~~