#include <bits/stdc++.h>

using namespace std;

const int N = 1007;
string v[N];
bool vis[N][N];
string ans[N][N];
queue<pair<int, int>> q;
int n, m;
int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};

void bfs(int x, int y) {
    vis[x][y] = true;
    q.push({x, y});
    while(!q.empty()) {
        auto p = q.front();
        q.pop();
        int i = p.first, j = p.second;
        for(int _ = 0; _ < 4; _++) {
            if(i + dx[_] >= 0 and i + dx[_] < n and j + dy[_] >= 0 and j + dy[_] < m and (v[i + dx[_]][j + dy[_]] == '.' or v[i + dx[_]][j + dy[_]] == 'B') and !vis[i + dx[_]][j + dy[_]]) {
                string s = ans[i][j];
                vis[i + dx[_]][j + dy[_]] = true;
                switch(_) {
                    case 0:
                        s += 'U';
                        ans[i + dx[_]][j + dy[_]] = s;
                        q.push({i + dx[_], j + dy[_]});
                        break;
                    case 1:
                        s += 'L';
                        ans[i + dx[_]][j + dy[_]] = s;
                        q.push({i + dx[_], j + dy[_]});
                        break;
                    case 2:
                        s += 'D';
                        ans[i + dx[_]][j + dy[_]] = s;
                        q.push({i + dx[_], j + dy[_]});
                        break;
                    case 3:
                        s += 'R';
                        ans[i + dx[_]][j + dy[_]] = s;
                        q.push({i + dx[_], j + dy[_]});
                        break;
                    default:
                        break;
                }
            }
        }
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    freopen("in.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    cin >> n >> m;
    for(int i = 0; i < n; i++) {
        cin >> v[i];
    }
    int xb = 0, yb = 0;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            if(v[i][j] == 'A') {
                bfs(i, j);
            }
            if(v[i][j] == 'B') {
                xb = i, yb = j;
            }
        }
    }
    if(!vis[xb][yb])  {
        cout << "NO\n";
    } else {
        cout << "YES\n";
        cout << ans[xb][yb].size() << "\n";
        cout << ans[xb][yb] << "\n";
    }
    return 0;
}