Puzzle 012: Hotel Rooms

ナゾ０１２　ホテルの部屋
ホテル内の１２室ある部屋すべての中に
入ってチェックしなければならない。
効率よくチェックするため、入り口から
同じ部屋に２度入らず、すべての部屋を
通って出口まで行きたい。一見難しい
ようにも思えるが、実はそのルートは
ある数字で表されるため、考えること
なくチェックを終わらせることができる
のだ。その数字とは何だかわかるかね。

Google Translate
12 must be checked in the hotel inside the room with all rooms. Efficient to check the room without entering the same two degrees from the entrance, go through all the rooms to the exit. First glance seem to be so difficult, in fact its root is represented by the numbers because they can bring an end to the check without thinking. Those are great numbers and you know me.

Notes on Puzzle
You are given an overhead view of the hotel rooms. Almost all the rooms are connected to their neighbors except for one pair. After finding a route through the floor plan that crosses through all rooms once, you'll see the route itself spells out a number. The number is the answer.