#include <bits/stdc++.h>
using namespace std;
using LL = long long;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

void solve() {
    int n, m;
    cin >> n >> m;
    vector<string> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    queue<pair<set<pair<int, int>>, string>> q;
    set<pair<int, int>> init;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (a[i][j] == '1') {
                init.emplace(i, j);
            }
        }
    }
    q.emplace(init, "");
    string d = "UDLR";
    int dx[] = {-1, 1, 0, 0};
    int dy[] = {0, 0, -1, 1};

    int mn = 1e9;
    while (!q.empty()) {
        auto [v, s] = q.front();
        q.pop();

        if (v.size() > mn) {
            continue;
        }
        mn = min(mn, (int)v.size());
        if (v.size() <= 1) {
            cout << s << "\n";
            return;
        }
        for (int i = 0; i < 4; i++) {
            set<pair<int, int>> st;
            for (auto [x, y] : v) {
                int nx = x + dx[i];
                int ny = y + dy[i];
                if (nx < 0 || nx >= n || ny < 0 || ny >= m || a[nx][ny] == '0') {
                    nx = x;
                    ny = y;
                }
                st.emplace(nx, ny);
            }
            q.emplace(st, s + d[i]);
        }
    }
}

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

    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}