#include using namespace std; using Int = long long; const char newl = '\n'; template inline void chmin(T1 &a,T2 b){if(a>b) a=b;} template inline void chmax(T1 &a,T2 b){if(a void drop(const T &x){cout< vector read(size_t n){ vector ts(n); for(size_t i=0;i>ts[i]; return ts; } template struct TopTree{ enum Type { Compress, Rake, Edge }; struct Node{ Vertex* vs[2]; Cluster dat; Node* p; Node* q; Node* ch[2]; bool rev,guard; Type type; Node():p(nullptr),q(nullptr),rev(false),guard(false){} }; static array pool_v; static array pool_c; size_t ptr_v,ptr_c; Cluster id; TopTree(Cluster id=Cluster()):ptr_v(0),ptr_c(0),id(id){} inline Vertex* create(Vertex v=Vertex()){ auto t=&pool_v[ptr_v++]; auto dummy=&pool_v[ptr_v++]; *t=v; link(t,id,dummy); return t; } inline Node* edge(Vertex* u,Cluster w,Vertex* v){ auto t=&(pool_c[ptr_c++]); t->vs[0]=u;t->vs[1]=v;t->dat=w;t->type=Type::Edge; return pushup(t); } inline Node* compress(Node* l,Node* r){ auto t=&(pool_c[ptr_c++]); t->ch[0]=l;t->ch[1]=r;t->type=Type::Compress; return pushup(t); } inline Node* rake(Node* l,Node* r){ auto t=&(pool_c[ptr_c++]); t->ch[0]=l;t->ch[1]=r;t->type=Type::Rake; return pushup(t); } Int parent_dir(Node* t){ Node* p=t->p; if(!p) return -1; if(p->guard) return -1; if(p->ch[0]==t) return 0; if(p->ch[1]==t) return 1; return -1; } Int parent_dir_ignore_guard(Node* t){ Node* p=t->p; if(!p) return -1; if(p->ch[0]==t) return 0; if(p->ch[1]==t) return 1; return -1; } inline Node* pushup(Node* const t){ Node* const l=t->ch[0]; Node* const r=t->ch[1]; if(t->type==Type::Compress){ assert(l->vs[1]==r->vs[0]); t->vs[0]=l->vs[0]; t->vs[1]=r->vs[1]; Cluster lf=l->dat; if(t->q){ assert(l->vs[1]==t->q->vs[1]); lf=Cluster::rake(l->dat,t->q->dat); } t->dat=Cluster::compress(lf,r->vs[0],r->dat); l->vs[1]->handle=t; } if(t->type==Type::Rake){ propagate(t); assert(l->vs[1]==r->vs[1]); t->vs[0]=l->vs[0]; t->vs[1]=l->vs[1]; t->dat=Cluster::rake(l->dat,r->dat); }else{ if(!t->p){ t->vs[0]->handle=t; t->vs[1]->handle=t; }else if(t->p->type==Type::Compress){ if(parent_dir(t)==-1) t->vs[0]->handle=t; }else if(t->p->type==Type::Rake){ t->vs[0]->handle=t; } } return t; } inline void toggle(Node* t){ if(t->type==Type::Edge){ swap(t->vs[0],t->vs[1]); t->dat.toggle(); }else if(t->type==Type::Compress){ swap(t->vs[0],t->vs[1]); t->dat.toggle(); t->rev^=true; }else if(t->type==Type::Rake){ }else abort(); } inline void propagate(Node* t){ if(t->type==Type::Compress){ if(t->rev){ assert(t->ch[0] and t->ch[1]); swap(t->ch[0],t->ch[1]); toggle(t->ch[0]); toggle(t->ch[1]); t->rev=false; } } } void set_toggle(Node* v){ toggle(v);propagate(v); } void pushdown(Node* t){ if(!t) return; pushdown(t->p); propagate(t); } void rotate(Node* t,Node* x,size_t dir){ Node* y=x->p; Int par=parent_dir_ignore_guard(x); propagate(t->ch[dir]); x->ch[dir^1]=t->ch[dir]; t->ch[dir]->p=x; t->ch[dir]=x; x->p=t; t->p=y; if(~par) y->ch[par]=t; else if(y and y->type==Type::Compress) y->q=t; pushup(x);pushup(t); if(y and !y->guard) pushup(y); } void splay(Node* t){ assert(t->type!=Type::Edge); propagate(t); while(~parent_dir(t)){ Node* q=t->p; if(q->type!=t->type) break; if(~parent_dir(q) and q->p and q->p->type==q->type){ Node* r=q->p; if(r->p) propagate(r->p); propagate(r);propagate(q);propagate(t); Int qt_dir=parent_dir(t); Int rq_dir=parent_dir(q); if(rq_dir==qt_dir){ rotate(q,r,rq_dir^1); rotate(t,q,qt_dir^1); }else{ rotate(t,q,qt_dir^1); rotate(t,r,rq_dir^1); } }else{ if(q->p) propagate(q->p); propagate(q);propagate(t); Int qt_dir=parent_dir(t); rotate(t,q,qt_dir^1); } } } Node* expose(Node* t){ pushdown(t); while(true){ assert(t->type!=Type::Rake); if(t->type==Type::Compress) splay(t); Node* n=nullptr; { Node* p=t->p; if(!p) break; if(p->type==Type::Rake){ propagate(p); splay(p); n=p->p; } if(p->type==Type::Compress){ propagate(p); if(p->guard and ~parent_dir_ignore_guard(t)) break; n=p; } } splay(n); Int dir=parent_dir_ignore_guard(n); if(dir==-1 or n->p->type==Type::Rake) dir=0; Node* const c=n->ch[dir]; if(dir==1){ set_toggle(c); set_toggle(t); } Int n_dir=parent_dir(t); if(~n_dir){ Node* const r=t->p; propagate(c); propagate(r); r->ch[n_dir]=c; c->p=r; n->ch[dir]=t; t->p=n; pushup(c);pushup(r);pushup(t);pushup(n); splay(r); }else{ propagate(c); n->q=c; c->p=n; n->ch[dir]=t; t->p=n; pushup(c);pushup(t);pushup(n); } if(t->type==Type::Edge) t=n; } return t; } Node* expose(Vertex* v){ return expose((Node*)(v->handle)); } void soft_expose(Vertex* u,Vertex* v){ pushdown((Node*)u->handle); pushdown((Node*)v->handle); Node* rt=expose(u); if(u->handle==v->handle){ if(rt->vs[1]==u or rt->vs[0]==v) set_toggle(rt); return; } rt->guard=true; Node* soft=expose(v); rt->guard=false; pushup(rt); if(parent_dir(soft)==0) set_toggle(rt); } void bring(Node* rt){ Node* rk=rt->q; if(!rk){ Node* ll=rt->ch[0]; ll->p=nullptr; pushup(ll); }else if(rk->type==Type::Compress or rk->type==Type::Edge){ propagate(rk); Node* nr=rk; set_toggle(nr); rt->ch[1]=nr; nr->p=rt; rt->q=nullptr; pushup(nr);pushup(rt); }else if(rk->type==Type::Rake){ propagate(rk); while(rk->ch[1]->type==Type::Rake){ propagate(rk->ch[1]); rk=rk->ch[1]; } pushdown(rk); rt->guard=true; splay(rk); rt->guard=false; Node* ll=rk->ch[0]; Node* rr=rk->ch[1]; propagate(ll); set_toggle(rr); rt->ch[1]=rr; rr->p=rt; rt->q=ll; ll->p=rt; pushup(ll);pushup(rr);pushup(rt); } } Node* link(Vertex* u,Cluster w,Vertex* v){ if(!u->handle and !v->handle) return edge(u,w,v); Node* nnu=(Node*)u->handle; Node* nnv=(Node*)v->handle; Node* ee=edge(u,w,v); Node* ll=nullptr; if(!nnv) ll=ee; else{ Node* vv=expose(nnv); propagate(vv); if(vv->vs[1]==v) set_toggle(vv); if(vv->vs[0]==v){ Node* nv=compress(ee,vv); ee->p=nv; pushup(ee); vv->p=nv; pushup(vv);pushup(nv); ll=nv; }else{ Node* nv=vv; Node* ch=nv->ch[0]; propagate(ch); nv->ch[0]=ee; ee->p=nv; pushup(ee); Node* bt=nv->q; Node* rk=nullptr; if(bt){ propagate(bt); rk=rake(bt,ch); bt->p=rk; ch->p=rk; pushup(bt);pushup(ch); }else{ rk=ch; } nv->q=rk; rk->p=nv; pushup(rk);pushup(nv); ll=nv; } } if(nnu){ Node* uu=expose(nnu); propagate(uu); if(uu->vs[0]==u) set_toggle(uu); if(uu->vs[1]==u){ Node* tp=compress(uu,ll); uu->p=tp; ll->p=tp; pushup(uu);pushup(ll);pushup(tp); }else{ Node* nu=uu; Node* ch=nu->ch[1]; toggle(ch); propagate(ch); nu->ch[1]=ll; ll->p=nu; pushup(ll); Node* al=nu->q; Node* rk=nullptr; if(al){ propagate(al); rk=rake(al,ch); al->p=rk; ch->p=rk; pushup(al);pushup(ch); }else{ rk=ch; } nu->q=rk; rk->p=nu; pushup(rk);pushup(nu); } } return ee; } void cut(Vertex* u,Vertex *v){ soft_expose(u,v); Node* rt=(Node*)u->handle; propagate(rt); Node* rr=rt->ch[1]; rr->p=nullptr; set_toggle(rr); bring(rr);bring(rt); } Node* path(Vertex* u,Vertex* v){ assert(u!=v); soft_expose(u,v); Node* rt=(Node*)u->handle; propagate(rt); propagate(rt->ch[1]); return rt->ch[1]->ch[0]; } void set_vertex(Vertex* u,Vertex v){ auto t=expose(u); *u=v; pushup(t); } void set_edge(Vertex* u,Vertex* v,const Cluster &w){ auto t=path(u,v); assert(t->type==Type::Edge); t->dat=w; while(t) pushup(t),t=t->p; } Cluster get_path(Vertex* u,Vertex* v){ return path(u,v)->dat; } Cluster get_subtree(Vertex* v){ return expose(v)->dat; } // subtree of v when p is root Cluster get_subtree(Vertex* p,Vertex* v){ Node* t=path(p,v); Cluster res=t->p->ch[1]->dat; res.toggle(); Node* rk=t->p->q; if(t->p->q){ assert(rk->vs[1]==t->p->ch[1]->vs[0]); res=Cluster::rake(res,rk->dat); } return res; } }; template array TopTree::pool_v; template array::Node, LIM> TopTree::pool_c; struct Vertex{ void* handle; Vertex():handle(nullptr){} }; const Int INF = 1e9 + 10; struct Cluster{ Int len; Int lft,rgh,mid,ans; Cluster(Int len=INF):len(len),lft(len),rgh(len),mid(INF),ans(INF){} void toggle(){ swap(lft,rgh); } static Cluster compress(Cluster x,Vertex *,Cluster y){ Cluster nxt(x.len+y.len); nxt.lft=y.lft; nxt.rgh=x.rgh; nxt.mid=INF; nxt.ans=min({x.ans,y.ans,x.mid}); return nxt; } static Cluster rake(Cluster x,Cluster y){ x.mid=min({x.mid,y.mid,y.lft}); return x; } }; //INSERT ABOVE HERE signed main(){ cin.tie(0); ios::sync_with_stdio(0); const size_t LIM = 1e6; TopTree T; Int n; cin>>n; vector vs(n); for(Int i=0;i>u>>v>>w; u--;v--; T.link(vs[u],Cluster(w),vs[v]); } Int q; cin>>q; for(Int i=0;i>x>>y; x--;y--; auto res=T.get_path(vs[x],vs[y]); Int ans=res.ans; chmin(ans,T.get_subtree(vs[x],vs[y]).lft); chmin(ans,T.get_subtree(vs[x],vs[y]).mid); chmin(ans,T.get_subtree(vs[y],vs[x]).lft); chmin(ans,T.get_subtree(vs[y],vs[x]).mid); if(ans==INF) cout<<-1<