// UUID: c09e3acc-d450-4cfc-8a35-e0d8a01c8a8a
#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> trie(25000*20+1, vector<int>(26, -1));
vector<bool> iswordend(25000*20+1, false);
vector<int> cnt(250*20+1, 0);
int nodes = 0;
vector<char> ops;
void insert(const string s){
int node = 0;
for(int i = 0; i < s.size(); i++) {
if (trie[node][s[i] - 'a'] == -1) trie[node][s[i] - 'a'] = ++nodes;
node = trie[node][s[i] - 'a'];
cnt[node]++;
if (i == s.size()-1) iswordend[node]=true;
}
}
void dfs(int node){
if (iswordend[node]) ops.push_back('P');
vector<pair<int, int>> curr; //longest, char's val
for(int i = 0; i < 26; i++) {
if (trie[node][i] != -1) curr.push_back({cnt[trie[node][i]], i});
}
sort(curr.begin(), curr.end());
for(auto i : curr){
ops.push_back((char) i.second + 'a');
dfs(trie[node][i.second]);
}
ops.push_back('-');
}
void solve() {
int n;
cin >> n;
for (int i = 0; i < n; i++){
string s;
cin >> s;
insert(s);
}
dfs(0);
for (int i = ops.size()-1; i >= 0; i--){
if (ops[i] != '-') break;
ops.pop_back();
}
cout << ops.size() << "\n";
for (char c : ops) cout << c << "\n";
return;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t = 1;
//cin >> t;
while (t--) {
solve();
}
return 0;
}
