NOBITA STAIRS

Nobita likes to jump on stairs. There is a stair ‘A‘ and each stair has a value Ai and Nobita will only make the jump from one stair ‘i’ to another stair ‘j’ if and only if they have equal values i.e.: Ai=Aj. Now since Nobita is very lazy, he will make only one jump and the distance of the jump should be minimum. For example if he could jump from stair ‘i’ to stair ‘j’, then j-i should be the min