#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<string> ans;
  char s[2];
  char e[2];
  cin >> s[0] >> s[1];
  cin >> e[0] >> e[1];
  int st[2] = {0, 0};
  int en[2] = {0, 0};
  st[0] = s[0] + 1 - 'a';
  en[0] = e[0] + 1 - 'a';
  st[1] = s[1] - '0';
  en[1] = e[1] - '0';
  int dis[2];
  dis[1] = en[1] - st[1];
  dis[0] = en[0] - st[0];
  while (dis[0] != 0 || dis[1] != 0) {
    if (dis[0] > 0 && dis[1] > 0) {
      ans.push_back("RU");
      dis[0]--;
      dis[1]--;
    }
    if (dis[0] > 0 && dis[1] < 0) {
      ans.push_back("RD");
      dis[0]--;
      dis[1]++;
    }
    if (dis[0] < 0 && dis[1] > 0) {
      ans.push_back("LU");
      dis[0]++;
      dis[1]--;
    }
    if (dis[0] < 0 && dis[1] < 0) {
      ans.push_back("LD");
      dis[0]++;
      dis[1]++;
    }
    if (dis[0] == 0 && dis[1] > 0) {
      ans.push_back("U");
      dis[1]--;
    }
    if (dis[0] == 0 && dis[1] < 0) {
      ans.push_back("D");
      dis[1]++;
    }
    if (dis[0] < 0 && dis[1] == 0) {
      ans.push_back("L");
      dis[0]++;
    }
    if (dis[0] > 0 && dis[1] == 0) {
      ans.push_back("R");
      dis[0]--;
    }
  }
  cout << ans.size() << endl;
  for (int i = 0; i < ans.size(); i++) {
    cout << ans[i] << endl;
  }
  return 0;
}
