#include <iostream>
#include <queue>
using namespace
 
 std;
int vis[101][101] = {0};
char map[101][101];
int dir[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
int n, m, flag, val;
struct point
{
    int x, y, num; //存點和當前深度
    point(int xx, int yy, int dd)
    {
        x = xx;
        y = yy;
        num = dd;
    } //解構函式便於初始化賦值,和class類相似的處理
};
queue<point> q;
 
void bfs(int sx, int sy)
{
    q.push(point(sx, sy, 0)); //放入起始位置點,從此開始
    vis[sx][sy] = 1;
    while (!q.empty())
    {
        point p = q.front();
        q.pop();                  //把裡元素依次取出,再將先放入點彈出(避免重複)
        if (map[p.x][p.y] == 'T') //找到終點記錄(bfs第一次找到的就是最短步)
        {
            val = p.num;//裝步數
 

            flag = 1;
            break;
        }
        for (int i = 0; i < 4; i++)
        {
            int a = p.x + dir[i][0];
            int b = p.y + dir[i][1]; //典中點之四向判斷
            if (map[a][b] != '#' && vis[a][b] == 0 && a >= 0 && a < n && b >= 0 && b < m)
            {
                q.push(point(a, b, p.num + 1));
                //將四周可行的點放入佇列後(加的這幾個點深度相同)
                vis[a][b] = 1; //來過了
            }
        }
    }
}
int main()
{
    int s1, s2;
    flag = 0;//標記找到與否
    cin >> n >> m;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            cin >> map[i][j];
            if (map[i][j] == 'S') //找到了入口
            {
                s1 = i;
                s2 = j;
            }
        }
    }
    bfs(s1, s2);
    if (flag == 0)
        cout << "-1";
    else
        cout << val << endl;
    return 0;
}