program P2099;
const
  mo=1000000007;
var
  i,n:longint;
  cnt:array[1..2] of longint;
  pres,dp:array[1..2] of int64;
  a:array[1..100010] of integer;
  ans:int64;

procedure inc0(var u:int64;v:int64);
begin
  u:=(u+v) mod mo;
end;

begin
  assign(input,'asm_code.in');assign(output,'asm_code.out');
  reset(input);rewrite(output);
  readln(n);
  for i:=1 to n do
    read(a[i]);
  for i:=1 to n do
  begin
    ans:=(ans+dp[a[i]]) mod mo;
    inc0(pres[a[i]],cnt[3-a[i]]);
    inc(cnt[a[i]]);
    inc0(dp[3-a[i]],pres[3-a[i]]);
  end;
  writeln(ans);
  close(input);close(output);
end.