#pragma warning(disable : 4996)
#include <iostream>
#include <vector>
#include <queue>
#include <string>

using namespace std;

void bfs(vector<vector<char>> &mapa, vector<vector<char>> &path, pair<int, int> start)
{
    queue<pair<int, int>> q;
    q.push(start);
    path[start.first][start.second] = 'S';

    while (!q.empty())
    {
        pair<int, int> v = q.front();
        q.pop();

        if (mapa[v.first - 1][v.second] != '#' && path[v.first - 1][v.second] == '-')
        {
            path[v.first - 1][v.second] = 'U';
            q.push({ v.first - 1, v.second });
        }
        if (mapa[v.first + 1][v.second] != '#' && path[v.first + 1][v.second] == '-')
        {
            path[v.first + 1][v.second] = 'D';
            q.push({ v.first + 1, v.second });
        }
        if (mapa[v.first][v.second - 1] != '#' && path[v.first][v.second - 1] == '-')
        {
            path[v.first][v.second - 1] = 'L';
            q.push({ v.first, v.second - 1 });
        }
        if (mapa[v.first][v.second + 1] != '#' && path[v.first][v.second + 1] == '-')
        {
            path[v.first][v.second + 1] = 'R';
            q.push({ v.first , v.second + 1});
        }
    }
}

int main()
{
    //freopen("pathbge1.in", "r", stdin);
    //freopen("pathbge1.out", "w", stdout);
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    int n, m;
    cin >> n >> m;
    getchar();
    vector<vector<char>> mapa(n + 2, vector<char>(m + 2, '#'));
    vector<vector<char>> path(n + 2, vector<char>(m + 2, '-'));

    pair<int, int> start;
    pair<int, int> finish;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            mapa[i][j] = getchar();
            if (mapa[i][j] == 'S')
                start = { i,j };
            if (mapa[i][j] == 'T')
                finish = { i,j };
        }
        getchar();
    }

    bfs(mapa, path, start);
    if (path[finish.first][finish.second] == '-')
    {
        cout << "-1";
        return 0;
    }
    else
    {
        string ans;
        pair<int, int> v = finish;
        while (v != start)
        {
            ans += path[v.first][v.second];
            if (path[v.first][v.second] == 'U') {
                v.first++;
            }
            else if (path[v.first][v.second] == 'D') {
                v.first--;
            }
            else if (path[v.first][v.second] == 'L') {
                v.second++;
            }
            else if (path[v.first][v.second] == 'R') {
                v.second--;
            }
        }
        reverse(ans.begin(), ans.end());
        cout << ans.size() << endl;
        cout << ans;
    }
    return 0;
}