Write a program that, given a map with treasures and obstacles, computes the distance from a given initial position to the nearest accessible treasure. The allowed movements are horizontal or vertical, but not diagonal.

Input

Input begins with the number of rows n > 0 and the number of columns m > 0 of the map. Follow n rows with m characters each. A dot indicates an empty position, an ‘X’ indicates an obstacle, and a ‘t’ indicates a treasure. Finally, two numbers r and c indicate the initial row and column (both of them starting at 1) where we must start looking for treasures. You can assume that r is between 1 and n, that c is between 1 and m, and that the initial position is always empty.

Output

Print the minimum number of steps to reach a treasure strating from the initial position. If no treasure is accessible, tell so.

Public test cases

**Input**

7 6 ..t... ..XXX. ...... tX..X. .X..Xt .XX... ..t... 5 3

**Output**

minimum distance: 4

**Input**

4 10 ..t...X... .....X..t. XXXXX.X... .......X.t 4 1

**Output**

no treasure can be reached

**Input**

5 7 ....... .XXXXXt .X...Xt .X.X.XX ...X.Xt 5 5

**Output**

minimum distance: 19

Information

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