#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};
string ds = "DURL";

struct node {
    string sp;
    int x, y;
};

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

    int n, m;
    cin >> n >> m;

    int s = 0, t = 0;
    vector a(n + 2, vector<int>(m + 2));
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            char ch;
            cin >> ch;
            a[i][j] = ch - '0';
            if (a[i][j] == 1) {
                s = i, t = j;
            }
        }
    }

    vector<string> ans;
    vector vis(n + 2, vector<int>(m + 2));
    queue<node> q;
    q.push({"", s, t});
    vis[s][t] = true;
    while (!q.empty()) {
        auto [sp, x, y] = q.front();
        q.pop();
        ans.push_back(sp);

        for (int i = 0; i < 4; i++) {
            int xx = x + dx[i], yy = y + dy[i];
            if (!vis[xx][yy] && xx >= 1 && xx <= n && yy >= 1 && yy <= m && a[xx][yy] == 1) {
                vis[xx][yy] = true;
                q.push({sp + ds[i], xx, yy});
            }
        }
    }

    map<int, vector<string>, greater<>> mp;
    for (int i = ans.size() - 1; i >= 1; i--) {
        reverse(ans[i].begin(), ans[i].end());
        mp[count(ans[i].begin(), ans[i].end(), 'U')].push_back(ans[i]);
        mp[count(ans[i].begin(), ans[i].end(), 'D')].push_back(ans[i]);
        mp[count(ans[i].begin(), ans[i].end(), 'L')].push_back(ans[i]);
        mp[count(ans[i].begin(), ans[i].end(), 'R')].push_back(ans[i]);
    }

    for (auto [x, y] : mp) {
        for (auto xx : y) {
            cout << xx;
        }
    }

    return 0;
}