#include <bits/stdc++.h>
using namespace std;
string s1, s2;
int main() {
  cin >> s1 >> s2;
  int x1 = s1[0] - 'a' + 1, y1 = s1[1] - '0', x2 = s2[0] - 'a' + 1,
      y2 = s2[1] - '0';
  int dis = max(abs(x1 - x2), abs(y1 - y2));
  printf("%d\n", dis);
  while (dis--) {
    if (x1 > x2 && y1 > y2) {
      x1--;
      y1--;
      printf("LD\n");
      continue;
    }
    if (x1 > x2 && y1 == y2) {
      x1--;
      printf("L\n");
      continue;
    }
    if (x1 > x2 && y1 < y2) {
      x1--;
      y1++;
      printf("LU\n");
      continue;
    }
    if (x1 == x2 && y1 > y2) {
      y1--;
      printf("D\n");
      continue;
    }
    if (x1 == x2 && y1 < y2) {
      y1++;
      printf("U\n");
      continue;
    }
    if (x1 < x2 && y1 > y2) {
      x1++;
      y1--;
      printf("RD\n");
      continue;
    }
    if (x1 < x2 && y1 == y2) {
      x1++;
      printf("R\n");
      continue;
    }
    if (x1 < x2 && y1 < y2) {
      x1++;
      y1++;
      printf("RU\n");
      continue;
    }
  }
  return 0;
}
