#include <iostream>

#include <string>

#include <queue>

using namespace std;

int n, m;

string maze[110];

bool vis[110][110];

int dir[4][2] = { {-1, 0}, {0, -1}, {1, 0}, {0, 1} };

bool in(int x, int y)

{

    return 0 <= x && x < n && 0 <= y && y < m;

}

struct node

{

  int x,y,d;

    node (int xx, int yy,int dd)

    {

        x = xx;

        y = yy;

        d = dd;

    }

};

int bfs(int sx, int sy)

{

    queue<node> q;

    q.push(node(sx,sy,0));

    vis[sx][sy] = true;

    while (!q.empty())

    {

        node now = q.front();

        q.pop();

        for(int i = 0; i < 4; i++)

        {

            int tx = now.x + dir[i][0];

            int ty = now.y + dir[i][1];

            if (in(tx,ty) && maze[tx][ty] != '*' && !vis[tx][ty])

            {

                if (maze[tx][ty] == 'T')

                {

                    return now.d + 1;

                }

                else

                {

                    vis [tx][ty] = true;

                    q.push(node(tx,ty,now.d + 1));

                }

            }

        }

    }

    return -1;

}

int main()

{

    cin >> n >> m;

    for (int i = 0; i < n; i++)

    {

        cin >> maze[i];

    }

    int x, y;

    for (int i = 0; i < n; i++)

    {

        for (int j = 0; j < m; j++)

        {

            if (maze[i][j] == 'S')

            {

                x = i, y = j;

            }

        }

    }

    cout << bfs(x,y) << endl;

    return 0;

}