#include <bits/stdc++.h> #include <iomanip> #define fast ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); #define ll long long #define ld long double #define el '\n' #define INF 1e18 //#define int ll using namespace std; const ll mod = 1e9 + 7; const ll inf = 1e9; const ll MOD = 998244353; const int MAXV = 200000; const int MOD1 = 1000000007; const int MOD2 = 1000000009; const int BASE = 911382323; int dx[4] = {-1,1,0,0}; int dy[4] = {0,0,-1,1}; struct Node { int next[26]; bool isWord; int mxD; Node() { memset(next, -1, sizeof(next)); isWord = false; mxD = 0; } }; vector<Node> trie; vector<char> ops; int calc(int u) { int best = trie[u].isWord ? 0 : -1; for (int c = 0; c < 26; c++) { int v = trie[u].next[c]; if (v != -1) { best = max(best, 1 + calc(v)); } } trie[u].mxD = best; return best; } void dfs(int u) { if (trie[u].isWord) { ops.push_back('P'); } vector<int> children; for (int c = 0; c < 26; c++) { if (trie[u].next[c] != -1) { children.push_back(c); } } sort(children.begin(), children.end(), [&](int a, int b) { return trie[trie[u].next[a]].mxD < trie[trie[u].next[b]].mxD; }); for (int c : children) { int v = trie[u].next[c]; ops.push_back('a' + c); dfs(v); ops.push_back('-'); } } void H_H() { int n; cin >> n; trie.reserve(500000); trie.emplace_back(); for (int i = 0; i < n; i++) { string s; cin >> s; int u = 0; for (char ch : s) { int c = ch - 'a'; if (trie[u].next[c] == -1) { trie[u].next[c] = trie.size(); trie.emplace_back(); } u = trie[u].next[c]; } trie[u].isWord = true; } calc(0); dfs(0); while (!ops.empty() && ops.back() == '-') { ops.pop_back(); } cout << ops.size() << el; for (char c : ops) { cout << c << el; } } signed main() { fast; ll tc = 1; //cin >> tc; while (tc--) { H_H(); } return 0; }