import java.util.*;

public class MyTest{
    static List<String> GetCombination(String[][] input){
        List<String> temp = new ArrayList<String>();
        List<String> result = new ArrayList<String>();
        result.add("");

        for (String[] a : input){
            for (String s : a){
                for (String r : result){
                    temp.add(s+r);
                }
            }
            result = new ArrayList<String>(temp);
            temp.clear();
        }

        return result;
    }

    public static void main(String[] args) {
        String[][] input = {
            { "a", "b", "c", "d", "e" },
            { "+", "-", "*", "/" },
            { "1", "2" },
        };

        List<String> result = GetCombination(input);
        System.out.println(result);
    }
}