import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
public class UVA_10047 {
	static int n, m;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (sc.hasNext()) {
			n = sc.nextInt();
			m = sc.nextInt();
			if (n == 0 && m == 0)
				break;
			char[][] map = new char[n][m];
			boolean[][][][] v = new boolean[4][5][n][m];
			for (int i = 0; i < n; i++)
				map[i] = sc.next().toCharArray();
			int sx = 0, sy = 0, ex = 0, ey = 0;

			for (int i = 0; i < n; i++)
				for (int j = 0; j < m; j++)
					if (map[i][j] == 'S') {
						sx = i;
						sy = j;
					} else if (map[i][j] == 'T') {
						ex = i;
						ey = j;
					}
			int t = bfs(map, v, sx, sy, ex, ey);
			System.out.println(t);
		}
	}
	static int[] dx = { -1, 0, 1, 0 };
	static int[] dy = { 0, 1, 0, -1 };

	private static int bfs(char[][] map2, boolean[][][][] v, int sx, int sy,
			int ex, int ey) {

		Queue<enternal> q = new LinkedList<enternal>();
		q.add(new enternal(sx, sy, 0, 0, 0));

		while (!q.isEmpty()) {
			enternal ob = q.poll();
			int x = ob.x;
			int y = ob.y;
			int t = ob.t;
			int dir = ob.dir;
			int color = ob.color;
			if (x == ex && y == ey && color == 0)
				return t;

			int newX = x + dx[dir];
			int newY = y + dy[dir];

			if (okay(map2, v, newX, newY, color, dir)) {
				q.add(new enternal(newX, newY, t + 1, color + 1, dir));
				v[dir][color][newX][newY] = true;
			}
			int newDir = (dir + 1) % 4;
			if (!v[newDir][color][x][y]) {
				q.add(new enternal(x, y, t + 1, color, newDir));
				v[newDir][color][x][y] = true;
			}
			newDir = dir == 0 ? 3 : dir - 1;
			if (!v[newDir][color][x][y]) {
				q.add(new enternal(x, y, t + 1, color, newDir));
				v[newDir][color][x][y] = true;
			}
		}
		return -1;
	}

	static boolean okay(char[][] map, boolean[][][][] v, int x, int y,
			int color, int dir) {
		return x >= 0 && y >= 0 && x < n && y < m && map[x][y] != '#'
				&& !v[dir][color][x][y];
	}
}
class enternal {
	int x, y, t, color, dir;
	public enternal(int x, int y, int t, int color, int dir) {
		this.x = x;
		this.y = y;
		this.t = t;
		this.color = color % 5;
		this.dir = dir;
	}
}