#include <bits/stdc++.h>
using namespace std;
long long xorn(long long n) {
  long long r = (n + 1) % 4;
  if (r == 0) return 0;
  if (r == 1) return n;
  if (r == 2) return 1;
  if (r == 3) return n + 1;
}
int main() {
  char a, b, c, d;
  int x, y, i;
  cin >> a >> b >> c >> d;
  x = c - a;
  y = d - b;
  cout << max(abs(x), abs(y)) << "\n";
  if (x >= 0) {
    if (y >= 0) {
      for (i = 0; i < min(x, y); i++) cout << "RU\n";
      if (y > x)
        for (i = 0; i < y - x; i++) cout << "U\n";
      else
        for (i = 0; i < x - y; i++) cout << "R\n";
    } else {
      y = -y;
      for (i = 0; i < min(x, y); i++) cout << "RD\n";
      if (y > x)
        for (i = 0; i < y - x; i++) cout << "D\n";
      else
        for (i = 0; i < x - y; i++) cout << "R\n";
    }
  } else {
    x = -x;
    if (y >= 0) {
      for (i = 0; i < min(x, y); i++) cout << "LU\n";
      if (y > x)
        for (i = 0; i < y - x; i++) cout << "U\n";
      else
        for (i = 0; i < x - y; i++) cout << "L\n";
    } else {
      y = -y;
      for (i = 0; i < min(x, y); i++) cout << "LD\n";
      if (y > x)
        for (i = 0; i < y - x; i++) cout << "D\n";
      else
        for (i = 0; i < x - y; i++) cout << "L\n";
    }
  }
}
