#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, x1, y, y1;
  char a, b;
  cin >> a >> y >> b >> y1;
  x1 = a - 96;
  x = b - 96;
  int counter = 0;
  string s[100000];
  while (true) {
    if (x == x1 && y == y1) {
      break;
    }
    if (x > x1) {
      x1++;
      s[counter] += 'R';
    }
    if (x < x1) {
      x1--;
      s[counter] += 'L';
    }
    if (y > y1) {
      y1++;
      s[counter] += 'D';
    }
    if (y < y1) {
      y1--;
      s[counter] += 'U';
    }
    counter++;
  }
  cout << counter << endl;
  for (int i = 0; i < counter; i++) {
    cout << s[i] << endl;
  }
}
