#include <bits/stdc++.h>
using namespace std;
const long long N = 2 * 1e6;
const long double EPS = 1e-8;
const long long INF = 2 * 1e9 + 1;
const long long MAX = 1e9;
vector<string> ans;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie();
  srand(time(NULL));
  char a1, a2, b1, b2;
  cin >> a1 >> b1 >> a2 >> b2;
  while (a1 < a2 && b1 < b2) {
    ans.push_back("RU");
    a1++, b1++;
  }
  while (a1 > a2 && b1 < b2) {
    ans.push_back("LU");
    a1--, b1++;
  }
  while (a1 < a2 && b1 > b2) {
    ans.push_back("RD");
    a1++, b1--;
  }
  while (a1 > a2 && b1 > b2) {
    ans.push_back("LD");
    a1--, b1--;
  }
  while (a1 == a2 && b1 < b2) {
    ans.push_back("U");
    b1++;
  }
  while (a1 == a2 && b1 > b2) {
    ans.push_back("D");
    b1--;
  }
  while (a1 < a2 && b1 == b2) {
    ans.push_back("R");
    a1++;
  }
  while (a1 > a2 && b1 == b2) {
    ans.push_back("L");
    a1--;
  }
  cout << ans.size() << endl;
  for (int i = 0; i < ans.size(); i++) cout << ans[i] << endl;
}
