How to use GetExternalFilesDirs in Android 4.4.2?

Use this:

Java.IO.File[] externalFilesDirs = GetExternalFilesDirs(null);
string s = externalFilesDirs[0].AbsolutePath;
Android.Widget.Toast.MakeText(this, s, Android.Widget.ToastLength.Long).Show();

Correctly get the path to sdcard0. While trying to get the path to sdcard1 error occurs. string s = externalFilesDirs[1].AbsolutePath; How can I make this folder on sdcard1? Use sdcard0 for me is not suitable, since little space. In the manifest:WRITE_EXTERNAL_STORAGE. How to tell the program to use sdcard1 instead of sdcard0? Thanks in advance!