#include <bits/stdc++.h>
using namespace std;
#define Kero \
ios_base::sync_with_stdio(0); \
cout.tie(0); \
cin.tie(0)
#define ll long long
#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define ld long double
#define pii pair<int, int>
#define endl '\n'
#define see(x) " [" << #x << " = " << (x) << "] "
const int INF = 1e9;
// Coding is so easy if you simulate on paper first
struct Trie
{
struct Node
{
int go[26]{};
int f[26]{};
bool isEnd= 0;
};
vector<Node> trie;
Trie()
{
trie.emplace_back();
}
void insert(string &s)
{
int cur = 0;
for (int i = 0; i < s.size(); i++)
{
int ch = s[i] - 'a';
if (!trie[cur].go[ch])
trie[cur].go[ch] = trie.size(), trie.emplace_back();
trie[cur].f[ch] = max(trie[cur].f[ch], (int)s.size());
cur = trie[cur].go[ch];
}
trie[cur].isEnd = 1;
}
vector<char> traverse()
{
vector<char> ret;
dfs(ret);
while (ret.back() == '-')
ret.pop_back();
return ret;
}
void dfs(vector<char> &ret, int cur = 0)
{
vector<pii> ordered;
if(trie[cur].isEnd)
ret.push_back('P');
for (int i = 0; i < 26; i++)
if (trie[cur].f[i] > 0)
ordered.push_back({trie[cur].f[i], i});
sort(all(ordered));
for (auto &[_, ch] : ordered)
ret.push_back(ch + 'a'), dfs(ret, trie[cur].go[ch]), ret.push_back('-');
}
};
void solve()
{
int n;
cin >> n;
Trie trie;
while (n--)
{
string s;
cin >> s;
trie.insert(s);
}
vector<char> ans = trie.traverse();
cout << ans.size() << endl;
for (auto &ch : ans)
cout << ch << endl;
}
signed main()
{
Kero;
int t = 1;
// cin >> t;
while (t--)
solve();
return 0;
}
