program zzn;
var
        n,i,j,m,u,v,s,x,y,z,ans,max,k:longint;
        a,aa:array[1..200,1..200]of longint;
        vv:array[1..200,1..200]of boolean;
        b:array[1..200,0..200]of longint;
        cost:array[1..10000]of longint;
procedure closef;
begin
        close(input);
        close(output);
end;
procedure init;
begin
        assign(input,'cost.in');
        reset(input);
        assign(output,'cost.out');
        rewrite(output);
        readln(n,m,u,v,s);
        if n>200 then
        begin
            writeln(-1);
            halt;
        end;
        fillchar(a,sizeof(a),255);
        fillchar(b,sizeof(b),0);
        for i:=1 to n do readln(cost[i]);
        for i:=1 to m do
        begin
                readln(x,y,z);
                a[x,y]:=z;
                a[y,x]:=z;
                inc(b[x,0]);
                inc(b[y,0]);
                b[x,b[x,0]]:=y;
                b[y,b[y,0]]:=x;
        end;
        fillchar(vv,sizeof(vv),0);
        aa:=a;
        for k:=1 to n do
         for i:=1 to n do if i<>k then
          for j:=1 to n do if j<>i then
           if (aa[k,j]<>-1)and(aa[i,k]<>-1)then
            if (aa[i,j]=-1)or(aa[i,j]>aa[i,k]+aa[k,j]) then
             aa[i,j]:=aa[i,k]+aa[k,j];
        if aa[u,v]>s then
         begin
             writeln(-1);
             closef;
             halt;
         end;
end;
procedure dfs(x:integer;cc,lu,ss:longint);
var
        i:integer;
begin
        if x=v then
        begin
        if lu>max then
        begin
            max:=cc;
            ans:=ss;
        end else
         if lu=max then
          if ss<ans then ans:=ss;
          exit;
        end;
        for i:=1 to b[x,0] do
          if cc+a[x,b[x,i]]<=s then
        begin
           if a[x,b[x,i]]>ss then ss:=a[x,b[x,i]];
           dfs(b[x,i],cc+a[x,b[x,i]],lu+cost[x],ss);
        end;
end;
procedure main;
begin
        ans:=maxlongint;
        max:=-maxlongint;
        dfs(u,0,0,-maxlongint);
        writeln(ans);
end;
begin
        init;
        main;
        closef;
end.