// source problem :
#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define int long long
#define MASK(i) (1LL << (i))
void ckmax(int& f, int s)
{
f = (f > s ? f : s);
}
void ckmin(int& f, int s)
{
f = (f < s ? f : s);
}
struct Trie
{
int cnt, e, mx;
Trie* child[26];
Trie()
{
mx = 0;
e = 0;
cnt = 0;
for (int i = 0; i < 26; i++) child[i] = NULL;
}
};
Trie* p = new Trie();
void insert(string s)
{
auto t = p;
for (char c : s)
{
if (!t->child[c - 'a']) t->child[c - 'a'] = new Trie();
t = t->child[c - 'a'];
t->cnt++;
ckmax(t->mx, (int)s.size());
}
t->e++;
}
string ans = "";
void get(Trie* cur)
{
if (cur->e)
{
ans += 'P';
}
vector<pair<int, int>> s;
for (int i = 0; i < 26; i++)
{
if (cur->child[i])
{
s.emplace_back(cur->child[i]->mx, i);
}
}
sort(s.begin(), s.end());
for (auto [fi, se] : s)
{
ans += (char)('a' + se);
get(cur->child[se]);
ans += '-';
}
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
for (int i = 0; i < n; i++)
{
string s;
cin >> s;
insert(s);
}
get(p);
string s = ans;
while (!s.empty() && s.back() == '-') s.pop_back();
cout << s.size() << '\n';
for (char c : s) cout << c << '\n';
return 0;
}
// n + tot_size * 2 - 2 * tot_lcp_adj - longest_sz
