#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int mN = 1e9;
int t, n, a2, b2;
char a1, b1;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> a1 >> a2 >> b1 >> b2;
  cout << (max(abs(a2 - b2), abs(a1 - b1))) << "\n";
  while (true) {
    if (a1 == b1 && a2 == b2) break;
    if (a1 < b1) {
      a1++;
      cout << "R";
    } else if (a1 > b1) {
      a1--;
      cout << "L";
    }
    if (a2 < b2) {
      a2++;
      cout << "U";
    } else if (a2 > b2) {
      a2--;
      cout << "D";
    }
    cout << "\n";
  }
}
