#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define inf LONG_MAX

using namespace std;

struct two
{
    ll x, y;
};

char board[1000][1000];

ll dst[1000][1000];

ll n, m, startX, startY, finishX, finishY;

bool can(ll a, ll b)
{
    return a < n && a >= 0 && b >= 0 && b < m;
}

vector <two> tp;

int main()
{
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);

    cin >> n >> m;

    for (int i = 0; i < n; ++i)
        for (int j = 0; j < m; ++j)
        {
            cin >> board[i][j];

            if (board[i][j] == 'T')
                tp.push_back({i, j});

            dst[i][j] = inf;
        }

    cin >> startX >> startY >> finishX >> finishY;

    startX--;
    startY--;

    finishX--;
    finishY--;

    queue <two> q;

    dst[startX][startY] = 0;

    q.push({startX, startY});

    while (!q.empty())
    {
        two cur = q.front();

        q.pop();

        if (can(cur.x + 1, cur.y) && dst[cur.x][cur.y] + 1 < dst[cur.x + 1][cur.y])
        {
            q.push({cur.x + 1, cur.y});

            dst[cur.x + 1][cur.y] = dst[cur.x][cur.y] + 1;
        }

        if (can(cur.x - 1, cur.y) && dst[cur.x][cur.y] + 1 < dst[cur.x - 1][cur.y])
        {
            q.push({cur.x - 1, cur.y});

            dst[cur.x - 1][cur.y] = dst[cur.x][cur.y] + 1;
        }
        //
        if (can(cur.x, cur.y + 1) && dst[cur.x][cur.y] + 1 < dst[cur.x][cur.y + 1])
        {
            q.push({cur.x, cur.y + 1});

            dst[cur.x][cur.y + 1] = dst[cur.x][cur.y] + 1;
        }

        if (can(cur.x, cur.y - 1) && dst[cur.x][cur.y] + 1 < dst[cur.x][cur.y - 1])
        {
            q.push({cur.x, cur.y - 1});

            dst[cur.x][cur.y - 1] = dst[cur.x][cur.y] + 1;
        }

        if (board[cur.x][cur.y] == 'T')
            for (auto c : tp)
                if (dst[cur.x][cur.y] < dst[c.x][c.y])
                {
                    q.push(c);

                    dst[c.x][c.y] = dst[cur.x][cur.y];
                }

    }

    if (dst[finishX][finishY] == inf)
        dst[finishX][finishY] = -1;

    cout << dst[finishX][finishY];

    return 0;
}