program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils;

const
  MAXIN = 2000;
  INF = 100000000000;

var
  n, s, f, i, j, ind, u, m, x, y, data: integer;
  a: array [1..MAXIN, 1..MAXIN] of int64;
  d, mark, b: array [1..MAXIN] of int64;
  min: int64;
begin
  readln(n, m, s, f);

  for i := 1 to n do
  begin
    mark[i] := 0;
    d[i] := INF;
    b[i] := 0;
  end;

  for i := 1 to m do
    for j := 1 to m do
      a[i][j] := 0;

  for i := 1 to n do
    read(b[i]);

  for i := 1 to m do
  begin
    readln(x, y, data);
    a[x][y] := data;
    a[y][x] := data;
  end;

  d[s] := 0;

  while (true) do
  begin
    ind := -1;
    min := INF;
    for i := 1 to m do
      if ((mark[i] = 0) and (d[i] <= min)) then
      begin
        ind := i;
        min := d[i];
      end;
    if (ind = -1) then
      break;
    mark[ind] := 1;
    for u := 1 to m do
      if ((a[ind][u] <> 0) and (mark[u] = 0) and (d[u] > d[ind] + a[ind][u]) and (((d[ind] + a[ind][u] < b[u]) and (b[u] <> 0)) or (b[u] = 0))) then
        d[u] := d[ind] + a[ind][u];
  end;

  if (d[f] <> INF) then
    writeln(d[f])
  else
    writeln(-1);

  readln;
  readln;

end.