#include <bits/stdc++.h>
using namespace std;
string Dc[8] = {"L", "R", "U", "D", "LU", "LD", "RU", "RD"};
int Dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1};
int Dy[8] = {0, 0, 1, -1, 1, -1, 1, -1};
int main() {
  vector<string> ans;
  string s1, s2;
  cin >> s1 >> s2;
  int x1 = s1[0] - 'a', y1 = s1[1] - '1';
  int x2 = s2[0] - 'a', y2 = s2[1] - '1';
  while (x1 != x2 || y1 != y2) {
    int dx = x2 - x1;
    if (dx > 0) dx = 1;
    if (dx < 0) dx = -1;
    int dy = y2 - y1;
    if (dy > 0) dy = 1;
    if (dy < 0) dy = -1;
    for (int i = 0; i < 8; ++i) {
      if (dx == Dx[i] && dy == Dy[i]) ans.push_back(Dc[i]);
    }
    x1 += dx;
    y1 += dy;
  }
  cout << ans.size() << endl;
  for (int i = 0; i < ans.size(); ++i) cout << ans[i] << endl;
  return 0;
}
