#include<iostream>
#include<cmath>
#include<vector>
#include<queue>
#include<set>
#include<cstring>
#include<iterator>
using namespace std;
int i, n, m, x, y, k, start, finish;
set <int> a[10005];
char l[105][105];
int ch;
queue <int> q;
int main()
{
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    	for (int j = 1; j <= m; j++)
    		cin >> l[i][j];
    for (i = 1; i <= n; i++)
    	for (int j = 1; j <= m; j++)
    	{
    		if (l[i][j] == 'T')
    			finish = i * m + j;
    		if (l[i][j] == 'S')
    			start = i * m + j;
    		if ((l[i][j] == '.')||(l[i][j] == 'T')||(l[i][j] == 'S'))
    		{
    			if (i > 1)
	    			if ((l[i - 1][j] == '.')||(l[i - 1][j] == 'T')||(l[i - 1][j] == 'S'))
	    			{
				        a[(i - 1) * m + j].insert(i * m + j);
				        a[i * m + j].insert((i - 1) * m + j);
					}
				if (i < n)
					if ((l[i + 1][j] == '.')||(l[i + 1][j] == 'T')||(l[i + 1][j] == 'S'))
					{
				        a[(i + 1) * m + j].insert(i * m + j);
				        a[i * m + j].insert((i + 1) * m + j);
					}
				if (j > 1)
					if ((l[i][j - 1] == '.')||(l[i][j - 1] == 'T')||(l[i][j - 1] == 'S'))
					{
				        a[i * m + j - 1].insert(i * m + j);
				        a[i * m + j].insert(i * m + j - 1);
					}
				if (j < m)
					if ((l[i][j + 1] == '.')||(l[i][j + 1] == 'T')||(l[i][j + 1] == 'S'))
					{
				        a[i * m + j + 1].insert(i * m + j);
				        a[i * m + j].insert(i * m + j + 1);
					}
			}
		}
	int b[(n + 1) * (m + 1)], way[(n + 1) * (m + 1)];
	for (i = 0; i < (n + 1) * (m + 1); i++)
	{
		b[i] = 0;
		way[i] = 0;
	}
    k = 1;
    q.push(start);
    while (!q.empty())
    {
        ch = q.front();
        q.pop();
        if (b[ch] == 0)
        {
            b[ch] = k;
            for (auto j = a[ch].begin(); j != a[ch].end(); j++)
                if (b[*j] == 0)
                {
                    q.push(*j);
                    if (way[*j] != 0)
                        way[*j] = min(way[*j], way[ch] + 1);
                    else
                    	way[*j] = way[ch] + 1;
                }
        }
    }
    if (way[finish] == 0)
    {
    	cout << -1;
    	return 0;
	}
	ch = finish;
	char route[way[ch] + 10];
	for (i = 0; i <= way[ch] + 1; i++)
		route[i] = ' ';
	i = way[finish];
	while(ch != start)
	{
		if (ch - m > 0)
			if ((way[ch] > way[ch - m]) && ((way[ch - m] > 0) || (ch - m == start)))
			{
				route[i] = 'D';
				ch = ch - m;
				i--;
			}
		if (ch + 1 <= n * m)
			if ((way[ch] > way[ch + 1]) && ((way[ch + 1] > 0) || (ch + 1 == start)))
			{
				route[i] = 'L';
				ch = ch + 1;
				i--;
			}
		if (ch - 1 > 0)
			if ((way[ch] > way[ch - 1]) && ((way[ch - 1] > 0) || (ch - 1 == start)))
			{
				route[i] = 'R';
				ch = ch - 1;
				i--;
			}
		if (ch + m <= n * m)
			if ((way[ch] > way[ch + m]) && ((way[ch + m] > 0) || (ch + m == start)))
			{
				route[i] = 'U';
				ch = ch + m;
				i--;
			}
	}
	cout << way[finish] << endl;
	for (i = 1; i <= way[finish]; i++)
		cout << route[i];
    return 0;
}
/*
5 4
.S..
###.
T...
.##.
....
*/