program cunzaiyufou;
var
  n,i,x,y,c,min,m:longint;
  map:array[0..1001,0..1001] of longint;
  bz:array[0..1000]of boolean;
  dist:array[0..1000]of longint;
procedure sousuo(k,v,father:longint);
var
  i:longint;
begin
  if k=n+2 then
  begin
    if dist[0]<min then
      min:=dist[0];
    exit
  end
  else
  for i:=0 to n do
    if (bz[i])and(i<>father)and(map[v,i]>0)and(map[v,i]+dist[v]<min) then
    begin
      bz[i]:=false;
      dist[i]:=dist[v]+map[v,i];
      sousuo(k+1,i,v);
      bz[i]:=true
    end
end;
begin
  assign (input,'exists.in');
  reset (input);
  assign (output,'exists.out');
  rewrite (output);
    readln (n);
    for i:=1 to n-1 do
    begin
      readln (x,y,c);
      map[x,y]:=c;
      map[y,x]:=c
    end;
    readln (m);
    for i:=1 to m+1 do
    begin
      readln (x,y,c);
      map[x,y]:=c;
      map[y,x]:=c
    end;
    for i:=0 to n do
      bz[i]:=true;
    dist[0]:=0;
    min:=maxlongint;
    sousuo(1,0,0);
    writeln (min);
  close (input);
  close (output)
end.