#include <bits/stdc++.h>
using namespace std;

int n, m;

pair<int, int> start;
pair<int, int> finish;

char mat[1001][1001];
bool used[1001][1001];
int dist[1001][1001];

int leftWall[1001][1001];
int rightWall[1001][1001];
int topWall[1001][1001];
int bottomWall[1001][1001];

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

void input() {
    scanf("%d %d", &n, &m);
    for (int i = 0; i < n; i++) {
        scanf("%s", mat[i]);
        for (int j = 0; j < m; j++) {
            if (mat[i][j] == 'S') {
                start = {i, j};
            }
            if (mat[i][j] == 'F') {
                finish = {i, j};
            }
        }
    }
}

void prepare() {
    for (int i = 0; i < n; i++) {
        int c = 0;
        for (int j = 0; j < m; j++) {
            if (mat[i][j] == '#') c = j;
            else leftWall[i][j] = c + 1;
        }

        c = m - 1;
        for (int j = m - 1; j >= 0; j--) {
            if (mat[i][j] == '#') c = j;
            else rightWall[i][j] = c - 1;
        }
    }

    for (int j = 0; j < m; j++) {
        int r = 0;
        for (int i = 0; i < n; i++) {
            if (mat[i][j] == '#') r = i;
            else topWall[i][j] = r + 1;
        }

        r = n - 1;
        for (int i = n - 1; i >= 0; i--) {
            if (mat[i][j] == '#') r = i;
            else bottomWall[i][j] = r - 1;
        }
    }
}

int solve() {
    queue<pair<int, int>> q;
    q.push(start);

    used[start.first][start.second] = true;

    while (q.empty() == false) {
        pair<int, int> node = q.front();
        q.pop();
        int r = node.first;
        int c = node.second;

        for (int i = 0; i < 4; i++) {
            int newr = r + op[i][0];
            int newc = c + op[i][1];

            if (newr < 0 or newr >= n or newc < 0 or newc >= m) {
                continue;
            }

            if (used[newr][newc] or mat[newr][newc] == '#') {
                continue;
            }

            dist[newr][newc] = dist[r][c] + 1;
            q.push({newr, newc});
            used[newr][newc] = true;
        }

        if (!used[r][leftWall[r][c]]) {
            dist[r][leftWall[r][c]] = dist[r][c] + 1;
            q.push({r, leftWall[r][c]});
            used[r][leftWall[r][c]] = true;
        }

        if (!used[r][rightWall[r][c]]) {
            dist[r][rightWall[r][c]] = dist[r][c] + 1;
            q.push({r, rightWall[r][c]});
            used[r][rightWall[r][c]] = true;
        }

        if (!used[topWall[r][c]][c]) {
            dist[topWall[r][c]][c] = dist[r][c] + 1;
            q.push({topWall[r][c], c});
            used[topWall[r][c]][c] = true;
        }

        if (!used[bottomWall[r][c]][c]) {
            dist[bottomWall[r][c]][c] = dist[r][c] + 1;
            q.push({bottomWall[r][c], c});
            used[bottomWall[r][c]][c] = true;
        }

        if (used[finish.first][finish.second]) {
            return dist[finish.first][finish.second];
        }
    }
    return -1;
}

int main() {
    input();
    prepare();
    printf("%d\n", solve());
    return 0;
}
/*
#########
#...#...#
#.#...#.#
#.#...#.#
#..###..#
##.....##
###...###
#.......#
#..###..#
#.#...#.#
#.#...#.#
#...#...#

*/