You are given a grid with both sides equal to . Rows and columns are numbered from to . There is a castle on the intersection (, ). In a single step you move from a point () to a point () if there is a straight horizontal line or a straight vertical line connecting these two and not containing any forbidden cell. Here, "X" denotes a forbidden cell.
Your task is to calculate the minimum number of steps it would take to move the castle from its initial position to the goal position ().
It is guaranteed that it is possible to reach the goal position from the initial position.
The first line contains an integer , the size of the grid.
The following lines contains a string of length that consists of one of the following characters: "X" or ".". Here, "X" denotes a forbidden cell, and "." denotes an allowed cell.
The last line contains , , denoting the initial position of the castle, and , , denoting the goal position. Here, , , and are space separated.
Output an integer denoting the minimum number of steps required to move the castle to the goal position.
0 0 0 2
Here is a path that one could follow in order to reach the destination in steps: