// [IOI2008] Type Printer
#include <bits/stdc++.h>
using namespace std;
const int SIG = 26, NN = 25000;
struct Node {
int ch[SIG];
bool mark, end;
} T[NN * 20];
int sz = 0;
void insert(const string& s) {
int u = 0;
for (char c : s) {
int d = c - 'a', &cu = T[u].ch[d];
if (!cu) cu = ++sz;
u = cu;
}
T[u].end = true;
}
void dfs(int u, string& ans) {
const Node& x = T[u];
if (x.end) ans += 'P'; // 单词结尾, 打印
int mi = -1;
for (int i = 0; i < SIG; ++i) {
int v = x.ch[i];
if (!v) continue;
if (T[v].mark)
mi = i; // 先不走最长的串
else
ans += i + 'a', dfs(v, ans); // 走其它串
}
if (mi != -1) // 走最长串
ans += mi + 'a', dfs(x.ch[mi], ans);
ans += '-';
}
int main() {
ios::sync_with_stdio(false), cin.tie(0);
int n;
cin >> n;
string s, l;
for (int i = 0; i < n; ++i) {
cin >> s, insert(s);
if (s.length() > l.length()) l = s;
}
for (size_t i = 0, u = 0; i < l.size(); i++) // 标记最长的单词
u = T[u].ch[l[i] - 'a'], T[u].mark = true;
s.clear(), dfs(0, s);
while (s.back() == '-') s.pop_back(); // 最后的字符全部删掉
cout << s.size() << "\n";
for (char c : s) cout << c << "\n";
return 0;
}
// P4683 [IOI2008] Type Printer 2.92s / 47.79MB / 1.11KB C++11
