#include <bits/stdc++.h>
#define mp make_pair
#define sz(x) (int) (x).size()
#define pb push_back
using namespace std;
using ll = long long;
const int MAXN = 1e5 + 5;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const ll INFLL = 0x3f3f3f3f3f3f3f3f;
const double EPS = 1e-6;
struct Node {
bool mark, on;
array<int, 26> nxt;
};
vector<Node> trie;
void insert(string &s) {
int cur = 0;
for (char ch : s) {
int c = ch - 'a';
if (trie[cur].nxt[c] == 0) {
trie[cur].nxt[c] = sz(trie);
trie.emplace_back();
}
cur = trie[cur].nxt[c];
}
trie[cur].on = true;
}
void dfs(int cur, vector<char> &out) {
if (trie[cur].on) {
out.push_back('P');
}
int marked_child = -1;
for (int i = 0; i < 26; i++) {
if (trie[cur].nxt[i]) {
if (trie[trie[cur].nxt[i]].mark) {
marked_child = i;
}
else {
out.push_back('a' + i);
dfs(trie[cur].nxt[i], out);
}
}
}
if (marked_child != -1) {
out.push_back('a' + marked_child);
dfs(trie[cur].nxt[marked_child], out);
}
if (!trie[cur].mark && cur > 0) {
out.push_back('-');
}
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int n;
cin >> n;
trie.emplace_back();
vector<string> words(n);
int mx_ind = 0;
for (int i = 0; i < n; i++) {
cin >> words[i];
insert(words[i]);
if (sz(words[mx_ind]) < sz(words[i])) {
mx_ind = i;
}
}
// mark all chars of longest word
int cur = 0;
for (char ch : words[mx_ind]) {
int c = ch - 'a';
cur = trie[cur].nxt[c];
trie[cur].mark = true;
}
vector<char> out;
out.reserve(n);
dfs(0, out);
cout << sz(out) << '\n';
for (char ch : out) {
cout << ch << '\n';
}
return 0;
}
