AssetDatabase class is missing

AssetDatabase class is missing in MonoDevelop. I’m trying to print line like this

alt text

and in does’t detects. And of course it doesn’t compiles. Should I download/import any libraries, or use another another IDE/reinstall MonoDevelop? Current version is 4.0.1

Solved my problem by myself. Just import library UnityEditor by writing

    using UnityEditor;

at the top.