Best high school prank - Easy as 1, 2, 4

Hope for the future generation! This is one of the best original pranks I have ever heard of.

At a high school in Montana, a group of students let three goats loose inside the school. But before turning them loose, they painted numbers on the sides of the goats: 1, 2, and 4. School Administrators spent most of the day looking for No. 3