// your code goes here
#include <iostream>
#include <algorithm>
 
using namespace std;
 
int main()
{
    string s, t;
    cin >> s >> t;
    cout << max(abs(s[0] - t[0]), abs(s[1] - t[1])) << endl;
    while (s != t)
    {
        if (s[0] < t[0])
        {
            cout << "R";
            s[0] += 1;
        }
        else if (s[0] > t[0])
        {
            cout << "L";
            s[0] -= 1;
        }
 
        if (s[1] < t[1])
        {
            cout << "U";
            s[1] += 1;
        }
        else if (s[1] > t[1])
        {
            cout << "D";
            s[1] -= 1;
        }
 
        cout << endl;
    }
    return 0;
}

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