#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
#define pii pair<int, int>
#define piii pair<pii, int>
#define vi vector<int>
#define vvi vector<vi>
#define vpii vector<pii>
#define vvpii vector<vpii>
#define f first
#define s second
#define oo 1000000001
#define eb emplace_back
#define pb push_back
#define mpr make_pair
#define size(v) (int)v.size()
#define ln '\n'
#define ull unsigned long long
#define ll long long
#define all(v) v.begin(), v.end()
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MAX = 5e5;
int trie[MAX][26];
int8_t depth[MAX];
bool isEnd[MAX];
int nxt = 0;
void add(string &s) {
int node = 0;
int8_t len = size(s);
for (char c : s) {
if (trie[node][c - 'a']) {
node = trie[node][c - 'a'];
depth[node] = max(depth[node], len);
} else {
node = trie[node][c - 'a'] = ++nxt;
depth[node] = len;
}
}
isEnd[node] = true;
}
string traverse(int node) {
string res = "";
if (isEnd[node]) res += 'P';
int imaxDep = -1;
for (int i = 0; i < 26; ++i) {
if (trie[node][i] && (imaxDep == -1 || depth[trie[node][i]] > depth[trie[node][imaxDep]])) {
imaxDep = i;
}
}
if (imaxDep != -1) {
for (int i = 0; i < 26; ++i) {
if (i != imaxDep && trie[node][i]) {
res += ('a' + i);
res += traverse(trie[node][i]);
res += '-';
}
}
res += ('a' + imaxDep);
res += traverse(trie[node][imaxDep]);
res += '-';
}
return res;
}
void solve() {
int n;
cin >> n;
string s;
for (int i = 0; i < n; ++i) {
cin >> s;
add(s);
}
string res = traverse(0);
while (res.back() == '-') res.pop_back();
cout << size(res) << ln;
for (char c : res) {
cout << c << ln;
}
}
int main() {
ios_base::sync_with_stdio(false);
solve();
return 0;
}
