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 [0..MAXIN, 0..MAXIN] of int64;
  d, mark, b: array [0..MAXIN] of int64;
  min: int64;

function min1(a1, b1: int64): int64;
begin
  if (a1 < b1) then
    min1 := a1
  else
    min1 := b1
end;

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
  begin
    Readln(b[i]);

    If (b[i] = 0) then

    B[i] := INF;

  end;

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

  D[0] := INF;
  d[s] := 0;

 for j := 1 to n do
  begin
    Ind := 0;
    For i := 1 to n do
      If  (mark[i] = 0) and (d[i] < d[ind]) then
        Ind := i;
    If (d[ind] = INF) then
      Break;
    mark[j] := 1;
    For u := 1 to n do
    If (a[ind, u] <> 0) and (d[ind] + a[ind, u] < b[u]) then
      D[u] := min1(d[u], d[ind] + a[ind, u]);
    mark[ind] := 1;
  end;

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

  readln;
  readln;

end.