#include <bits/stdc++.h>
using namespace std;
int main() {
  char xn, yn, xm, ym;
  cin >> xn >> yn >> xm >> ym;
  cout << max(abs(xn - xm), abs(yn - ym)) << endl;
  char a = 'U', b = 'R';
  if (yn > ym) {
    a = 'D';
  }
  if (xn > xm) {
    b = 'L';
  }
  for (int i = 1; i <= min(abs(xn - xm), abs(yn - ym)); i++) {
    cout << b << a << endl;
  }
  if (abs(xn - xm) > abs(yn - ym)) {
    for (int i = min(abs(xn - xm), abs(yn - ym)) + 1;
         i <= max(abs(xn - xm), abs(yn - ym)); i++) {
      cout << b << endl;
    }
  } else {
    for (int i = min(abs(xn - xm), abs(yn - ym)) + 1;
         i <= max(abs(xn - xm), abs(yn - ym)); i++) {
      cout << a << endl;
    }
  }
  return 0;
}
