#include <bits/stdc++.h>
using namespace std;
int visited[100005];
int indegree[26];
int exists[26] = {0};
vector<vector<int>> edges;
stack<int> answer;
void dfs(int i)
{
    visited[i] = 1;
    cout << edges[i].size() << endl;
    for(int j = 0;j < edges[i].size();j++)
    {
        if(!visited[edges[i][j]] && exists[edges[i][j]])
            dfs(edges[i][j]);
    }
    answer.push(i);
}
int main()
{
    //freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    string temp,s;
    cin >> temp;
    edges.assign(30,vector<int>());
    do
    {
        cin >> s;
        if(s!="#")
            for(int i = 0;i < min(s.length(),temp.length());i++)
            {
                exists[(s[i]-'A')] = 1;
                exists[(s[i+1]-'A')] = 1;
                if(s[i] != temp[i])
                {
                    edges[temp[i]-'A'].push_back(s[i]-'A');
                    indegree[s[i]-'A'] = max(indegree[temp[i]-'A'],indegree[s[i]-'A']+1);
                    break;
                }
            }
        temp = s;
    } while(s!="#");
    for(int i = 0;i < 26;i++)
        if(exists[i] == 1 && !visited[i] && indegree[i] == 0)
            dfs(i);
    while(!answer.empty())
    {
        cout << (char)(answer.top()+'A');
        answer.pop();
    }
    return 0;
}