#include <iostream> #include <string> int n; std::string res = "", maxS = ""; std::string a[100005]; int pos = -1; int numbPrints = 0; struct node { node *child[26]; bool type = false; int numbWords = 0; }; node *createNode() { node *ret = new node(); ret->numbWords = 0; ret->type = false; for (int c = 0; c < 26; c++) { ret->child[c] = NULL; } return ret; } void addWord(node *root, const std::string &s, bool type) { node *p = root; for (int i = 0; i < (int) s.size(); i++) { if (p->child[s[i] - 'a'] == NULL) { p->child[s[i] - 'a'] = createNode(); } p = p->child[s[i] - 'a']; p->type = type; } p->numbWords++; } void dfs(node *root) { for (int i = 1; i <= root->numbWords; i++) { res += 'P'; numbPrints++; if (numbPrints == n) { std::cout << (int) res.size() << std::endl; for (int i = 0; i < (int) res.size(); i++) { std::cout << res[i] << std::endl; } exit(0); } } char chLast = '.'; for (int c = 0; c < 26; c++) { if (root->child[c] == NULL) { continue; } if (root->child[c]->type == true) { chLast = (char) (c + 'a'); break; } } for (int c = 0; c < 26; c++) { if (root->child[c] == NULL || (char) (c + 'a') == chLast) { continue; } res += (char) (c + 'a'); dfs(root->child[c]); res += '-'; } if (chLast != '.') { res += chLast; dfs(root->child[chLast - 'a']); } } int main () { node *root = createNode(); std::cin >> n; for (int i = 1; i <= n; i++) { std::string s; std::cin >> s; a[i] = s; if ((int) maxS.size() < (int) s.size()) { maxS = s; pos = i; } } for (int i = 1; i <= n; i++) { if (i != pos) { addWord(root, a[i], false); } } addWord(root, a[pos], true); dfs(root); return 0; }