#include<bits/stdc++.h>

using namespace std;

struct Point
{
    int i, j;
};

int n, m;
const int INF = (int)1e9;

bool can(Point p)
{
    return 0 <= p.i && 0 <= p.j && p.i < n && p.j < m;
}

main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m;
    vector<vector<bool>> p(n, vector<bool>(m));
    Point start, finish;
    for(int i = 0; i < n; i++)
    {
        string s;
        cin >> s;
        for(int j = 0; j < m; j++)
        {
            if(s[j] == 'S')
                start = {i, j}, p[i][j] = true;
            if(s[j] == 'F')
                finish = {i, j}, p[i][j] = true;
            if(s[j] == '.')
                p[i][j] = true;
        }
    }
    queue<Point> q;
    q.push(start);
    vector<vector<int>> dp(n, vector<int>(m, INF));
    vector<vector<bool>> vis(n, vector<bool> (m, false));
    dp[start.i][start.j] = 0;
    while(!q.empty())
    {
        Point cur = q.front();
        q.pop();
        vis[cur.i][cur.j] = true;
        for(int i = 1; ; i++)
        {
            Point next = {cur.i + i, cur.j};
            if(can(next) && p[next.i][next.j] && !vis[next.i][next.j] && dp[next.i][next.j] == INF)
            {
                dp[next.i][next.j] = dp[cur.i][cur.j] + 1,
                q.push(next);
            }
            else
                break;
        }
        for(int i = -1; ; i--)
        {
            Point next = {cur.i + i, cur.j};
            if(can(next) && p[next.i][next.j] && !vis[next.i][next.j] && dp[next.i][next.j] == INF)
            {
                dp[next.i][next.j] = dp[cur.i][cur.j] + 1,
                q.push(next);
            }
            else
                break;
        }
        for(int j = 1; ; j++)
        {
            Point next = {cur.i, cur.j + j};
            if(can(next) && p[next.i][next.j] && !vis[next.i][next.j] && dp[next.i][next.j] == INF)
            {
                dp[next.i][next.j] = dp[cur.i][cur.j] + 1,
                q.push(next);
            }
            else
                break;
        }
        for(int j = -1; ; j--)
        {
            Point next = {cur.i, cur.j + j};
            if(can(next) && p[next.i][next.j] && !vis[next.i][next.j] && dp[next.i][next.j] == INF)
            {

                dp[next.i][next.j] = dp[cur.i][cur.j] + 1,
                q.push(next);
            }
            else
                break;
        }
    }
    if(dp[finish.i][finish.j] == INF)
        cout << -1;
    else
        cout << dp[finish.i][finish.j];
}