#include<bits/stdc++.h>
using namespace std ;
int main() {
ios_base::sync_with_stdio(false) ;
cin.tie(NULL);
int t ;
vector<string > s ;
cin >> t ;
t = t+1;
while(t--) {
string str , stt ;
getline(cin,str) ;

transform(str.begin(),str.end(),str.begin(),::tolower);
for(int i = 0 , len = str.length(); i < len ; ++ i ) {
if(ispunct(str[i])) {
str.erase(i--,1) ;
len = str.length() ;
}
}
stringstream ss ;
ss << str ;
while(ss >> stt ) {
s.push_back(stt) ;

}

}
sort(s.begin() , s.end());
for(auto i = s.begin() ; i!=s.end() ; ++ i ) {

if((*i)==(*(i+1))){
s.erase(i);
i--;
}
}
cout << s.size() << endl;
for(auto &value : s)
cout << value << endl;
}

i don't no why it showing me fatal error