// Telebe of adicto yani AzeTurk810
//
// WHY ARE YOU STARING MY CODE Stranger ??!!
//
//GO AWAY AND DON T look my CODE if i don t know you or you are stalker !!!!(hrrr)
//
// here about me: I am alone of course, fun , ' , ' , love pyhcics , young(child) , love music , had birds , not a gamer , chess :) , dead to football , you are looking to code , ... ;
//
// why at 1 japon army march they say "the enemy geniral is a hero , an equal to no one. Both in glory and in victory
// the men that follow him are also breave , fearless wariors ..."?
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
# define ln '\n'
# define ff first
# define ss second
# define INFll 1e17
string res;
struct trie {
vector<trie*> child;
int finish = false;
int nodess;
trie() {
child.assign(26 , nullptr);
finish = false;
nodess = 0;
};
void print(trie *node) {
if(node -> nodess == 1 && node -> finish == 1) {
res.push_back('P');
res.push_back('-');
return;
}
while(node -> finish--) {
res.push_back('P');
}
vector<pair<int,char>> cur;
for(int i = 0 ; i < 26 ; i++) {
if(node -> child[i]) {
cur.push_back({(node -> child[i]) -> nodess , char(i + 'a')});
}
}
sort(cur.begin() , cur.end());
for(int i = 0 ; i < cur.size() ; i ++ ) {
res.push_back(cur[i].ss);
print(node -> child[cur[i].ss - 'a']);
}
res.push_back('-');
}
void ins(string &s) {
trie *node = this;
for(char c:s ) {
int id = c - 'a';
if(!node -> child[id]) {
node -> child[id] = new trie();
}
node -> nodess++;
node = node -> child[id];
}
node -> nodess++;
node -> finish++;
}
bool askk(int &k , int l) {
trie *node = this;
return query(k , l , node);
}
bool query(int &k , int l , trie *node) {
bool ok = false;
if(node -> nodess < k) return false;
if(!l) {
return node -> nodess >= k;
}
for(int i = 0 ; i < 26 ; i++) {
if(node -> child[i]) {
trie *cur = node -> child[i];
if(cur -> nodess >= k) {
ok |= query(k , l - 1 , cur);
}
if(ok) return ok;
}
}
return ok;
}
bool ask(string &s) {
trie *node = this;
for(char &c : s) {
int id = c - 'a';
if(!node -> child[id]) return false;
node = node -> child[id];
}
return node -> finish;
}
void del(string &s) {
trie *node = this;
for(char &c : s){
int id = c - 'a';
node -> nodess--;
node = node -> child[id];
}
node -> nodess--;
node -> finish--;
}
void print() {
print(this);
}
};
void solve() {
int q;
cin >> q;
trie root;
string s;
int ec = q;
while(q--) {
cin >> s;
root.ins(s);
}
root.print();
int cnt = 0;
q = ec;
string ans;
for(char &c: res) {
if(c == 'P') cnt++;
ans.push_back(c);
if(cnt >= q) break;
}
cout << ans.size() << ln;
for(char &c : ans) {
cout << c << ln;
}
}
signed main() {
// build();
int t = 1;
for(int cases = 1 ; cases <= t; cases++) {
solve();
}
}
