// UUID: 22542b23-9cb3-46a9-80fa-5322a384f0e7 #include <bits/stdc++.h> using namespace std; const int MAXN=20*25000+1; int trie[MAXN][26]; vector<int> word; vector<char> ki; int cnt=1; char szent; void add(string s){ int cur=0; for(char z:s){ if(!trie[cur][z-'a']) trie[cur][z-'a']=cnt++; cur=trie[cur][z-'a']; if(word[cur]==-1) word[cur]=0; } word[cur]++; } void dfs(int x){ for(int i=0; i<26; i++){ if(word[trie[x][i]]==-1||(x==0&&i==szent-'a')) continue; ki.push_back(i+'a'); dfs(trie[x][i]); } if(word[x]>0) ki.push_back('P'); ki.push_back('-'); } void dfs2(int x){ for(int i=0; i<26; i++){ if(word[trie[x][i]]==-1) continue; ki.push_back(i+'a'); dfs(trie[x][i]); } if(word[x]>0) ki.push_back('P'); ki.push_back('-'); } int main() { int n; cin>>n; vector<pair<int, char>> kak; word.resize(n*20+1, -1); for(int i=0; i<n; i++){ string s; cin>>s; add(s); kak.push_back({s.size(), s[0]}); } sort(kak.rbegin(), kak.rend()); szent=kak[0].second; dfs(0); ki.push_back(szent); dfs2(trie[0][szent-'a']); int a=ki.size()-1; while(ki[a]=='-') a--; cout<<a<<"\n"; for(int i=0; i<=a; i++) cout<<ki[i]<<"\n"; }