#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int main(){
	string s,e;
	while(cin>>s>>e){
		int step=0;
		int sx=s[0],sy=s[1];
		int ex=e[0],ey=e[1];
		string ss[10];//
//		cout<<sx<<" "<<sy<<endl;
//		cout<<ex<<" "<<ey<<endl;
		while(1){
			if(ex>sx&&ey>sy){
				sx++;sy++;
				ss[step]="RU";//cout<<"RU"<<endl;
				step++;
			}else if(ex==sx&&ey>sy){
			 	sy++;
			 	ss[step]="U";//cout<<"U"<<endl;
			 	step++;
			}else if(ex>sx&&ey==sy){
				sx++;
				ss[step]="R";//cout<<"R"<<endl;
				step++;
			}else if(ex<sx&&ey<sy){
				sx--;sy--;
				ss[step]="LD";//cout<<"LD"<<endl;
				step++;
			}else if(ex==sx&&ey<sy){
			 	sy--;
			 	ss[step]="D";//cout<<"D"<<endl;
			 	step++;
			}else if(ex<sx&&ey==sy){
				sx--;
				ss[step]="L";//cout<<"L"<<endl;
				step++;
			}else if(ex<sx&&ey>sy){
				sx--;sy++;
				ss[step]="LU";//cout<<"LU"<<endl;
				step++;
			}else if(ex>sx&&ey<sy){
				sx++;sy--;
				ss[step]="RD";//cout<<"RD"<<endl;
				step++;
			}
			
			if(ex==sx&&ey==sy){
				break;
			}
		}
		cout<<step<<endl;
		for(int i=0;i<step;i++){
			cout<<ss[i]<<endl;
		}
	}
	
	return 0;
}