#include <bits/stdc++.h>
using namespace std;
int main() {
  int steps;
  int move[2];
  char c1[2];
  char c2[2];
  c1[0] = getchar();
  c1[1] = getchar();
  getchar();
  c2[0] = getchar();
  c2[1] = getchar();
  move[0] = c1[0] - c2[0];
  move[1] = c1[1] - c2[1];
  steps = max(abs(c1[0] - c2[0]), abs(c1[1] - c2[1]));
  cout << steps << endl;
  for (int i = 0; i < steps; i++) {
    if (move[0] < 0 && move[1] < 0)
      cout << "RU" << endl, move[0]++, move[1]++;
    else if (move[0] < 0 && move[1] == 0)
      cout << "R" << endl, move[0]++;
    else if (move[0] < 0 && move[1] > 0)
      cout << "RD" << endl, move[0]++, move[1]--;
    else if (move[0] == 0 && move[1] < 0)
      cout << "U" << endl, move[1]++;
    else if (move[0] == 0 && move[1] > 0)
      cout << "D" << endl, move[1]--;
    else if (move[0] > 0 && move[1] < 0)
      cout << "LU" << endl, move[0]--, move[1]++;
    else if (move[0] > 0 && move[1] == 0)
      cout << "L" << endl, move[0]--;
    else if (move[0] > 0 && move[1] > 0)
      cout << "LD" << endl, move[0]--, move[1]--;
  }
  return 0;
}
