Untitled

#include <bits/stdc++.h>
 
using namespace std;
 
void File() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
#ifdef MON
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    freopen("errors.txt", "w", stderr);
#else
#endif
}
 
int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, 1, -1};
char di[] = {'D', 'U', 'R', 'L'};
 
int main() {
    File();
    int n, m;
    cin >> n >> m;
    char a[n][m];
    queue<pair<int, int>> q;
    vector<vector<bool>> vis(n, vector<bool>(m, false));
    vector<vector<int>> par(n, vector<int>(m));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            cin >> a[i][j];
            if (a[i][j] == 'A') {
                q.push({i, j});
                vis[i][j] = true;
                par[i][j] = -1;
            }
        }
    }
    while (!q.empty()) {
        int i = q.front().first, j = q.front().second;
        q.pop();
        for (int k = 0; k < 4; ++k) {
            int ni = i + dx[k], nj = j + dy[k];
            if (ni >= 0 && ni < n && nj >= 0 && nj < m && a[ni][nj] != '#' && !vis[ni][nj]) {
                q.push({ni, nj});
                par[ni][nj] = k;
                vis[ni][nj] = true;
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            if (a[i][j] == 'B') {
                if (vis[i][j]) {
                    cout << "YES\n";
                    vector<char> path;
                    int x = i, y = j;
                    while (par[x][y] != -1) {
                        int k = par[x][y];
                        x = x - dx[k], y = y - dy[k];
                        path.push_back(di[k]);
                    }
                    cout << path.size() << "\n";
                    reverse(path.begin(), path.end());
                    for (auto &c: path) cout << c;
                } else {
                    cout << "NO\n";
                }
            }
        }
    }
    return 0;
}