program xxxx;
var a1,a2,a3,n,m,u,v,s,i,j,k,max:longint;
    f:array[1..3500,1..3500,0..1] of longint;
    a:array[1..10000] of longint;

function maxx(x,y:longint):longint;
begin
  if x>y then
    maxx:=x
  else
    maxx:=y;
end;


begin
  assign(input,'cost.in');
  reset(input);
  assign(output,'cost.out');
  rewrite(output);
  read(n,m,u,v,s);
  max:=maxlongint;
  for i:=1 to n do
    read(a[i]);
  for i:=1 to n do
    for j:=1 to n do
      begin
        f[i,j,0]:=max;
        f[i,j,1]:=max;
      end;
  for i:=1 to m do
    begin
      read(a1,a2,a3);
      f[a1,a2,0]:=a3;
      f[a1,a2,1]:=maxx(a[a1],a[a2]);
      f[a2,a1,0]:=a3;
      f[a2,a1,1]:=f[a1,a2,1];
    end;
  for k:=1 to n do
    for i:=1 to n do
      for j:=1 to n do
        if (f[i,k,0]<max)and(f[j,k,0]<max) then
          if f[i,k,0]+f[j,k,0]<=s then
            if maxx(f[i,k,1],f[j,k,1])<f[i,j,1] then
              begin
                f[i,j,1]:=maxx(f[i,k,1],f[j,k,1]);
                f[i,j,0]:=f[i,k,0]+f[j,k,0];
              end;
  if f[u,v,1]<max then
    write(f[u,v,1])
  else
    write('-1');
  close(input);
  close(output);
end.