Problem Description

Find the shortest path from start (S) to treasure (T) in a grid map. The grid contains walls (#) that block movement, open paths (.), start position (S), and treasure position (T). You can move in 4 directions: up, down, left, right.

Input Format

First line contains m and n (grid dimensions). Next m lines contain the grid with characters: S (start), T (treasure), # (wall), . (path).

Output Format

Minimum steps to reach treasure from start, or -1 if impossible.

Constraints

• 1 ≤ m, n ≤ 100

• Exactly one S and one T in the grid

• Movement in 4 directions only

• Cannot move through walls (#)

• Each step counts as 1 unit

Sample Input/Output

4 4
S...
.##.
....
...T

6

Explanation

Shortest path from S to T: S→right→right→right→down→down→down→T. Total steps: 6.