// compile: g++ -o data data.cpp -std=gnu++20 -DLOCAL -g
// run: ./data < data.in
#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#ifdef LOCAL
#endif
#define sz(v) ((int)(v).size())
#define PV(v) for (int i=0;i<v.size();++i)cout<<v[i]<<" ";cout<<endl;
#define OK cout<<"OK"<<endl;
#define INTINF 9223372036854775807
#define int long long
#define MAXN 1010

using namespace std;

int n = 0, s, d;
int dir[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
int f[MAXN][MAXN];
int pre[MAXN*MAXN];
vector<int> e[MAXN*MAXN];
pair<int, int> coor[MAXN*MAXN];

struct node {
    int x, dis;
};

vector<node> q;
int bfs(int s, int d) {
    vector<int> vis(n, 0); vis[s] = 1;
    int head = 0, tail = -1;
    ++tail; q.push_back({s, 0});
    while (head <= tail) {
        node u = q[head++];
        // for (auto v = e[u.x].begin(); v != e[u.x].end(); ++v) {
        for (auto v = e[u.x].begin(); v != e[u.x].end(); ++v) {
            if (vis[*v]) continue;
            ++tail; q.push_back({*v, u.dis + 1});
            vis[*v] = 1;
            pre[tail] = head - 1;
            if (*v == d) return tail;
        }
    }
    return -1;
}

char direction(int u, int v) {
    pair<int, int> x = coor[u];
    pair<int, int> y = coor[v];
    int d = -1;
    for (int i = 0; i < 4; ++i) {
        if (x.first + dir[i][0] == y.first && x.second + dir[i][1] == y.second) {
            d = i;
            break;
        }
    }
    if (d == 0) return 'R';
    else if (d == 1) return 'D';
    else if (d == 2) return 'L';
    else if (d == 3) return 'U';
    else return '!';
}

void travesal(int last) {
    cout << q[last].dis << endl;
    vector<int> a;
    for (int i = last; ~i; i = pre[i]) a.push_back(q[i].x);
    reverse(a.begin(), a.end());
    for (int i = 0; i < sz(a)-1; ++i) cout << direction(a[i], a[i+1]);
    cout << endl;
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

    memset(f, -1, sizeof(f));
    memset(pre, -1, sizeof(pre));
    int mapn, mapm; cin >> mapn >> mapm;
    for (int i = 0; i < mapn; ++i) {
        string str; cin >> str;
        for (int j = 0; j < str.length(); ++j) {
            if (str[j] == 'A') s = n, coor[n] = make_pair(i, j), f[i+1][j+1] = n++;
            else if (str[j] == 'B') d = n, coor[n] = make_pair(i, j), f[i+1][j+1] = n++;
            else if (str[j] == '.') coor[n] = make_pair(i, j), f[i+1][j+1] = n++;
        }
    }
    for (int i = 1; i <= mapn; ++i) {
        for (int j = 1; j <= mapm; ++j) {
            if (!~f[i][j]) continue;
            for (int k = 0; k < 4; ++k) {
                if (~f[i + dir[k][0]][j + dir[k][1]]) e[f[i][j]].push_back(f[i + dir[k][0]][j + dir[k][1]]);
            }
        }
    }
    // for (int i = 1; i <= mapn; ++i) {
    //     for (int j = 1; j <= mapm; ++j) {
    //         cout << f[i][j] << "\t";
    //     }
    //     cout << endl;
    // }
    // for (int i = 0; i < n; ++i) {
    //     cout << i << ":\t";
    //     for (auto it = e[i].begin(); it != e[i].end(); ++it) {
    //         cout << (*it) << "\t";
    //     }
    //     cout << endl;
    // }
    // return 0;
    int last = bfs(s, d);
    if (~last) {
        cout << "YES" << endl;
        travesal(last);
    }
    else cout << "NO" << endl;

    return 0;
}