#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
#include <unordered_map>
#include <unordered_set>
#define ll long long
#define ld long double
#define pl pair<ll, ll>
#define vi vector<long long>
#define vii vector<vi>
#define vc vector<char>
#define vcc vector<vc>
#define vp vector<pl>
#define mi map<ll,ll>
#define mc map<char,int>
#define sortx(X) sort(X.begin(),X.end());
#define all(X) X.begin(),X.end()
#define allr(X) X.rbegin(),X.rend()
#define ln '\n'
#define YES {cout << "YES\n"; return;}
#define NO {cout << "NO\n"; return;}
#define MUN {cout << "-1\n"; return;}
using namespace std;
class Trie
{
public:
struct trie_node
{
ll cnt;
ll mx;
int next[26];
trie_node() {
cnt = mx = 0;
memset(next, -1, sizeof(next));
}
};
ll get(string &res) {return (get(0, res));}
void add(string &s) {add(0, s, 0, 0);}
Trie() {tree.resize(1, trie_node());}
private:
vector<trie_node> tree;
ll get(ll m, string &res) {
for (int i = 0; i < tree[m].cnt; i++)
{
res += "P";
}
for (int i = 0; i < 26; i++)
{
if (tree[m].next[i] != -1 && tree[tree[m].next[i]].mx != tree[m].mx) {
res += (char) 'a'+i;
get(tree[m].next[i], res);
res += '-';
}
}
for (int i = 0; i < 26; i++)
{
if (tree[m].next[i] != -1 && tree[tree[m].next[i]].mx == tree[m].mx) {
res += (char) 'a'+i;
get(tree[m].next[i], res);
res += '-';
}
}
return 0;
}
void add(ll m, string &s, ll h, ll idx) {
tree[m].mx = max(tree[m].mx, h);
if (!s[idx]) {
tree[m].cnt++;
return;
}
int nxt = s[idx] - 'a';
if (tree[m].next[nxt] == -1) {
tree[m].next[nxt] = tree.size();
tree.push_back(trie_node());
}
add(tree[m].next[nxt], s, h+1,idx + 1);
tree[m].mx = max(tree[m].mx, tree[tree[m].next[nxt]].mx);
}
};
const int MODE = 1e9+7;
void solve(int tc) {
ll n;
cin >> n;
Trie tr;
for (int i = 0; i < n; i++)
{
string s; cin >> s;
tr.add(s);
}
string res = "";
tr.get(res);
while (res.back() == '-')
{
res.pop_back();
}
cout << res.size() << '\n';
for (auto c : res) cout << c << '\n';
}
signed main()
{
ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
int size = 1;
// freopen("dec.in", "r", stdin);
// freopen("dec.out", "w", stdout);
// cin >> size;
for (int i = 1; i <= size; i++)
solve(i);
}
