#include <bits/stdc++.h>
int chuyen(char a) { return (int)a - (48 * 2); }
using namespace std;
int main() {
  string a[100];
  string s, t;
  int x = 0, tmp;
  cin >> s >> t;
  if (chuyen(s[0]) >= chuyen(t[0])) {
    while (true) {
      if (s[1] < t[1]) {
        if (s[1] == t[1]) {
          for (int i = 0; i < s[0] - t[0]; i++) {
            a[x] = "L";
            x++;
          }
          break;
        }
        if (s[0] == t[0]) {
          for (int i = 0; i < t[1] - s[1]; i++) {
            a[x] = "U";
            x++;
          }
          break;
        }
        a[x] = "LU";
        x++;
        s[1]++;
        s[0]--;
      } else {
        if (s[1] == t[1]) {
          for (int i = 0; i < s[0] - t[0]; i++) {
            a[x] = "L";
            x++;
          }
          break;
        }
        if (s[0] == t[0]) {
          for (int i = 0; i < s[1] - t[1]; i++) {
            a[x] = "D";
            x++;
          }
          break;
        }
        a[x] = "LD";
        x++;
        s[1]--;
        s[0]--;
      }
    }
  } else {
    while (true) {
      if (s[1] <= t[1]) {
        if (s[0] == t[0]) {
          for (int i = 0; i < t[1] - s[1]; i++) {
            a[x] = "U";
            x++;
          }
          break;
        }
        if (s[1] == t[1]) {
          for (int i = 0; i < t[0] - s[0]; i++) {
            a[x] = "R";
            x++;
          }
          break;
        }
        a[x] = "RU";
        x++;
        s[1]++;
        s[0]++;
      } else {
        if (s[0] == t[0]) {
          for (int i = 0; i < s[1] - t[1]; i++) {
            a[x] = "D";
            x++;
          }
          break;
        }
        if (s[1] == t[1]) {
          for (int i = 0; i < t[0] - s[0]; i++) {
            a[x] = "R";
            x++;
          }
          break;
        }
        a[x] = "RD";
        x++;
        s[0]++;
        s[1]--;
      }
    }
  }
  cout << x << "\n";
  for (int i = 0; i < x; i++) {
    cout << a[i] << "\n";
  }
}
