#include <bits/stdc++.h>
using namespace std;
const static int NUMPOINTS = 3;
const double PI = acos(-1.0);
class Solution {
 public:
  void solve() {
    char start_c, target_c;
    int start_i, target_i, hor_dif, ver_dif, step = 0;
    cin >> start_c >> start_i >> target_c >> target_i;
    hor_dif = target_c - start_c;
    ver_dif = target_i - start_i;
    step = max(abs(hor_dif), abs(ver_dif));
    int hor_step = (hor_dif > 0 ? 1 : -1);
    int ver_step = (ver_dif > 0 ? 1 : -1);
    cout << step << endl;
    for (int i = 0; i < step; ++i) {
      if (hor_dif) {
        cout << (hor_step == 1 ? 'R' : 'L');
        hor_dif -= hor_step;
      }
      if (ver_dif) {
        cout << (ver_step == 1 ? 'U' : 'D');
        ver_dif -= ver_step;
      }
      cout << endl;
    }
  }
};
int main() {
  Solution().solve();
  return 0;
}
