#include <bits/stdc++.h>
#define int long long
using namespace std;
int trie[500002][26], d[500002], mx[500002], id=0, end_[500002];
constexpr int ROOT = 0;
vector<char> ans;
void dfs(int depth = 0, int cur = ROOT) {
d[cur] = depth;
mx[cur] = d[cur];
for (int i = 0; i < 26; i++) {
if (!trie[cur][i])
continue;
dfs(depth + 1, trie[cur][i]);
mx[cur] = max(mx[cur], mx[trie[cur][i]]);
}
}
void dfs_ans(int cur = ROOT) {
if (end_[cur])
ans.push_back('P');
for (int c = 0; c < 26; c++) {
if (!trie[cur][c] || mx[cur] == mx[trie[cur][c]])
continue;
ans.push_back('a' + c);
dfs_ans(trie[cur][c]);
}
for (int c = 0; c < 26; c++) {
if (!trie[cur][c] || mx[cur] != mx[trie[cur][c]])
continue;
ans.push_back('a' + c);
dfs_ans(trie[cur][c]);
}
ans.push_back('-');
}
void add_string(string const & s) {
int cur = ROOT;
for (auto & c : s) {
int x = c - 'a';
if (trie[cur][x]) {
cur = trie[cur][x];
} else {
cur = trie[cur][x] = ++id;
}
}
end_[cur] = 1;
}
signed main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int n; cin >> n;
string s;
for (int i = 0; i < n; i++)
cin >> s, add_string(s);
dfs(); dfs_ans();
while(ans.back() != 'P')
ans.pop_back();
cout << (int) ans.size() << '\n';
for (int i = 0; i < (int) ans.size(); i++)
cout << ans[i] << '\n';
}
