#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")


constexpr int DX[4] = {+1, 0, -1, 0};
constexpr int DY[4] = {0, +1, 0, -1};
constexpr char DRUL[5] = "DRUL";

int M, N;
char A[30][30];

int V;
int ids[30][30];
int graph[410][4];

int dist[410][410];
int prv[410][410];

int main() {
  for (; ~scanf("%d%d", &M, &N); ) {
    for (int x = 0; x < M; ++x) {
      scanf("%s", A[x]);
    }
    
    V = 0;
    memset(ids, ~0, sizeof(ids));
    for (int x = 0; x < M; ++x) for (int y = 0; y < N; ++y) if (A[x][y] == '1') {
      ids[x][y] = V++;
    }
    for (int x = 0; x < M; ++x) for (int y = 0; y < N; ++y) {
      const int u = ids[x][y];
      if (~u) {
        for (int dir = 0; dir < 4; ++dir) {
          const int xx = x + DX[dir];
          const int yy = y + DY[dir];
          graph[u][dir] = (0 <= xx && xx < M && 0 <= yy && yy < N && ~ids[xx][yy]) ? ids[xx][yy] : u;
        }
      }
    }
    
    queue<pair<int, int>> que;
    memset(dist, ~0, sizeof(dist));
    memset(prv, ~0, sizeof(prv));
    for (int u = 0; u < V; ++u) {
      dist[u][u] = 0;
      que.emplace(u, u);
    }
    for (; !que.empty(); ) {
      const int u = que.front().first;
      const int v = que.front().second;
      que.pop();
      for (int dir = 0; dir < 4; ++dir) {
        for (const int uu : {u, graph[u][dir ^ 2]}) if (graph[uu][dir] == u)
        for (const int vv : {v, graph[v][dir ^ 2]}) if (graph[vv][dir] == v)
        {
          if (!~dist[uu][vv]) {
            dist[uu][vv] = dist[u][v] + 1;
            prv[uu][vv] = dir;
            que.emplace(uu, vv);
          }
        }
      }
    }
    for (int u = 0; u < V; ++u) for (int v = 0; v < V; ++v) {
      assert(~dist[u][v]);
    }
    
    vector<int> us(V);
    for (int u = 0; u < V; ++u) {
      us[u] = u;
    }
    string ans;
    for (; us.size() > 1; ) {
      int mn = V * V;
      int um = -1, vm = -1;
      for (int i = 0; i < (int)us.size(); ++i) for (int j = i + 1; j < (int)us.size(); ++j) {
        if (chmin(mn, dist[us[i]][us[j]])) {
          um = us[i];
          vm = us[j];
        }
      }
      for (int u = um, v = vm; u != v; ) {
        const int dir = prv[u][v];
        ans += DRUL[dir];
        u = graph[u][dir];
        v = graph[v][dir];
        for (int &w : us) {
          w = graph[w][dir];
        }
      }
      sort(us.begin(), us.end());
      us.erase(unique(us.begin(), us.end()), us.end());
    }
    
    puts(ans.c_str());
  }
  return 0;
}