#include <bits/stdc++.h>
using namespace std;
int main() {
  string s, t;
  cin >> s >> t;
  int left, right, up, down;
  if (s[0] >= t[0]) {
    left = s[0] - t[0];
    if ((s[1] - '0') < (t[1] - '0')) {
      up = (t[1] - '0') - (s[1] - '0');
      int minn = min(left, up);
      left -= minn, up -= minn;
      cout << minn + left + up << endl;
      for (int i = 0; i < minn; i++) cout << "LU" << endl;
      for (int i = 0; i < left; i++) cout << "L" << endl;
      for (int i = 0; i < up; i++) cout << "U" << endl;
    } else {
      down = (s[1] - '0') - (t[1] - '0');
      int minn = min(left, down);
      left -= minn, down -= minn;
      cout << minn + left + down << endl;
      for (int i = 0; i < minn; i++) cout << "LD" << endl;
      for (int i = 0; i < left; i++) cout << "L" << endl;
      for (int i = 0; i < down; i++) cout << "D" << endl;
    }
  } else {
    right = t[0] - s[0];
    if ((s[1] - '0') < (t[1] - '0')) {
      up = (t[1] - '0') - (s[1] - '0');
      int minn = min(right, up);
      right -= minn, up -= minn;
      cout << minn + right + up << endl;
      for (int i = 0; i < minn; i++) cout << "RU" << endl;
      for (int i = 0; i < right; i++) cout << "R" << endl;
      for (int i = 0; i < up; i++) cout << "U" << endl;
    } else {
      down = (s[1] - '0') - (t[1] - '0');
      int minn = min(right, down);
      right -= minn, down -= minn;
      cout << minn + right + down << endl;
      for (int i = 0; i < minn; i++) cout << "RD" << endl;
      for (int i = 0; i < right; i++) cout << "R" << endl;
      for (int i = 0; i < down; i++) cout << "D" << endl;
    }
  }
  return 0;
}
