#include <iostream>
#include <queue>
 
#include <bits/stdc++.h>
using namespace std;
char mat[1111][1111];
bool visited[1111][1111];
int prev_steps[1111][1111];
int main() {
    ios_base::sync_with_stdio(false);
    
    int n, m;
    cin >> n >> m;
    int si, sj, ei, ej;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            cin >> mat[i][j];
            visited[i][j] = false;
            if(mat[i][j] == 'A') {
                si = i; sj = j;
            }
            if(mat[i][j] == 'B') {
                ei = i; ej = j;
            }
        }
    }
    int di[] = {1, -1, 0, 0};
    int dj[] = {0, 0, 1, -1};
    queue<int> Q;
    Q.push(si); Q.push(sj); Q.push(0);
    visited[si][sj] = true;
    int dist = -1;
    while(!Q.empty()) {
        int ci = Q.front(); Q.pop();
        int cj = Q.front(); Q.pop();
        int cekor = Q.front(); Q.pop();
        
        if(ci == ei and cj == ej) {
            dist = cekor;
            break;
        }
        for(int i = 0; i < 4; i++) {
            int ti = ci + di[i];
            int tj = cj + dj[i];
            if(ti >= 0 and ti < n and tj >= 0 and tj < m and !visited[ti][tj] and mat[ti][tj] != '#') {
                Q.push(ti);
                Q.push(tj);
                Q.push(cekor + 1);
                visited[ti][tj] = true;
                prev_steps[ti][tj] = i;
            }
        }
    }
    if(dist == -1) {
        cout << "NO" << endl;
        return 0;
    }
    cout << "YES" << endl << dist << endl;
    pair<int, int> S = make_pair(si, sj), E = make_pair(ei, ej);
    string result = "";
    while(E != S) {
        int dir = prev_steps[E.first][E.second];
        if(dir == 0) {
            result += "D";
        }
        else if(dir == 1) {
            result += "U";
        }
        else if(dir == 2) {
            result += "R";
        }
        else {
            result += "L";
        }
        E = make_pair(E.first - di[dir], E.second - dj[dir]);
    }
    reverse(result.begin(), result.end());
    cout << result << endl;
    return 0;
}