Grid Maze X75212

A maze has been drawn on the graph paper. All walls are either horizontal or vertical.

Your task is simple: find the shortest route from the red dot to the green dot. You can only move horizontally or vertically.

NOTE: We assume that you can move very close to the walls (at distance 0).

Input

The first line contains five numbers: $N, X_1, Y_1, X_2, Y_2$. Here $N$ ($1 \leq N \leq 500$) is the number of lines in the maze, $(X_1, Y_1)$ are the coordinates of the red dot, and $(X_2, Y_2)$ are the coordinates of the green dot.

Each of the following $N$ lines describe one wall of the maze. A wall is described as four numbers $x_1, y_1, x_2, y_2$, where either $y_1 = y_2$ or $x_1 = x_2$.

All coordinates are in range $[-2000000000, +2000000000]$.

Output

Output the length of the shortest route between the two dots. You should output IMPOSSIBLE if there is no route.

You obtain a route of length 17 by moving very close to the endings of both inner walls.