#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
vector<int> v[100005];
int vis[100005];
bool isPrime(int n) {
  if (n <= 1) return false;
  for (int i = 2; i < n; i++)
    if (n % i == 0) return false;
  return true;
}
int binomialCoeff(int n, int k) {
  if (k == 0 || k == n) return 1;
  return binomialCoeff(n - 1, k - 1) + binomialCoeff(n - 1, k);
}
long long power(long long a, long long b) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = (ans * a) % MOD;
    b /= 2;
    a = (a * a) % MOD;
  }
  return ans;
}
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  string s1, s2;
  cin >> s1 >> s2;
  cout << max(abs(s1[0] - s2[0]), abs(s1[1] - s2[1])) << endl;
  while (s1 != s2) {
    if (s1[0] < s2[0]) {
      cout << "R";
      s1[0]++;
    }
    if (s1[0] > s2[0]) {
      cout << "L";
      s1[0]--;
    }
    if (s1[1] < s2[1]) {
      cout << "U";
      s1[1]++;
    }
    if (s1[1] > s2[1]) {
      cout << "D";
      s1[1]--;
    }
    cout << endl;
  }
}
