#include <bits/stdc++.h> // #include <ext/pb_ds/assoc_container.hpp> // #include <ext/pb_ds/tree_policy.hpp> // #include <ext/rope> using namespace std; // using namespace __gnu_pbds; typedef long long ll; typedef unsigned long long ull; typedef unsigned int uint; typedef long double ld; template <class T> using VV = vector<vector<T>>; using VI = vector<int>; using VVI = vector<vector<int>>; using VL = vector<long long>; using VVL = vector<vector<long long>>; using VC = vector<char>; using VVC = vector<vector<char>>; using VB = vector<bool>; using VVB = vector<vector<bool>>; using VD = vector<double>; using VVD = vector<vector<double>>; using PII = pair<int, int>; using PLL = pair<long long, long long>; using PIL = pair<int, long long>; using PLI = pair<long long, int>; using VPII = vector<pair<int, int>>; using VPLL = vector<pair<long long, long long>>; #define LINE '\n' #define SPACE ' ' #define PB push_back #define FOR(i, a, b) for (int i = (a); i < (int(b)); i++) #define FORE(i, a, b) for (int i = (a); i <= (int)((b)); i++) #define ALL(x) x.begin(), x.end() #define RALL(x) x.rbegin(), x.rend() #define sq(a) ((a) * (a)) #define sz(x) ((int)x.size()) #define fastio() \ ios_base::sync_with_stdio(false); \ cin.tie(nullptr); \ cout.tie(nullptr) #define debug(x) cerr << #x << " = " << x << endl; const ll MOD = 1e9 + 7; template <class T> inline void maxi(T &a, T b) { a = max(a, b); } template <class T> inline void mini(T &a, T b) { a = min(a, b); } template <class T> inline void addi(T &a, T b) { a = (a + b) % MOD; } template <class T> inline void subi(T &a, T b) { a = (a - b + MOD) % MOD; } template <class T> inline T add(T a, T b) { return (a + b) % MOD; } template <class T> inline T sub(T a, T b) { return (a - b + MOD) % MOD; } template <class T> inline T mul(T a, T b) { return ((a % MOD) * (b % MOD)) % MOD; } constexpr ll binpow(ll a, ll b, ll mod) { ll res = 1; while (b > 0) { if (b & 1) { res = (res * a) % mod; } a = (a * a) % mod; b >>= 1; } return res; } const int INF = 1e9; const int MAX_N = 2e5 + 3; static const int MAX_W = 1e6 + 5; struct Trie { int triesz; array<array<int, 26>, MAX_W> next; array<int, MAX_W> ends; Trie() : triesz(0) { FOR(i, 0, MAX_W) { next[i].fill(-1); } } void add(string &s) { int node = 0; for (char c : s) { if (next[node][c - 'a'] != -1) { node = next[node][c - 'a']; } else node = next[node][c - 'a'] = ++triesz; } ends[node]++; } }; Trie trie; string ans = ""; array<int, MAX_W> deep; array<int, MAX_W> dvert; void dfs_deep(int node, int d = 0) { deep[node] = 0; FOR(i, 0, 26) { if (int v = trie.next[node][i]; v != -1) { dfs_deep(v, d + 1); if (deep[node] == -1 || deep[node] < deep[v] + 1) { dvert[node] = i; deep[node] = deep[v] + 1; } } } } void dfs(int node, char c) { ans.push_back(c); FOR(i, 0, trie.ends[node]) { ans.push_back('P'); } FOR(i, 0, 26) { if (i == dvert[node]) continue; if (int v = trie.next[node][i]; v != -1) { dfs(v, char('a' + i)); } } if (int i = dvert[node]; i != -1) dfs(trie.next[node][i], char('a' + i)); ans.push_back('-'); } void solve() { dvert.fill(-1); deep.fill(0); int n; cin >> n; FOR(i, 0, n) { string s; cin >> s; trie.add(s); } dfs_deep(0); dfs(0, 0); ans.erase(0, 1); while (ans.back() == '-') ans.pop_back(); cout << sz(ans) << LINE; for (auto c : ans) { cout << c << LINE; } } int main() { fastio(); int t = 1; // cin >> t; while (t--) solve(); }