#include <bits/stdc++.h>
using namespace std;
void solve() {
  string a, b;
  cin >> a >> b;
  int x, y, c = 0;
  x = b[0] - a[0];
  y = b[1] - a[1];
  cout << max(abs(x), abs(y)) << endl;
  while (x || y) {
    if (x > 0) {
      x--;
      cout << "R";
    }
    if (x < 0) {
      x++;
      cout << "L";
    }
    if (y > 0) {
      y--;
      cout << "U";
    }
    if (y < 0) {
      y++;
      cout << "D";
    }
    cout << endl;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t = 1;
  while (t--) {
    solve();
    cout << "\n";
  }
  cerr << "time taken : " << (float)clock() / CLOCKS_PER_SEC << " secs" << endl;
  return 0;
}
