Find all the paths that a tortoise can travel
from an initial position to a final position.
The ground has *n* × *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.

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

Public test cases

**Input**

2 2 IG BA 1 0 0 1

**Output**

BIG BAG

**Input**

3 2 ab de ab 0 0 2 1

**Output**

adab adeb abeb abedab

**Input**

1 1 A 0 0 0 0

**Output**

A

Information

- Author
- Salvador Roura
- Language
- English
- Translator
- Carlos Molina
- Original language
- Catalan
- Other languages
- Catalan
- Official solutions
- C++
- User solutions
- C++