The travelling tortoise P22295

Find all the paths that a tortoise can travel from an initial position to a final position. The ground has $n \times m$ paving stones, each one with a letter painted on it. The tortoise can only make horizontal and vertical movements, and it cannot pass by the same position twice.

Input

Input begins with $n$ and $m$, followed by $n$ lines with $m$ letters each. Follow a pair of natural numbers indicating the initial row and column, and a pair of naturals numbers indicating the final row and column. The upper-left corner corresponds to the position $(0, 0)$.

Output

Print all the paths from the initial position to the final position.

Information about the checker

You can print the solutions to this exercise in any order.