// input checker 
#include <vector>
#include <iostream>
#include <cassert>
#include <set>
using namespace std;

int main(){
  int n;
  cin >> n;
  if( (1<=n && n<=20) == false ){
    cerr << "invalid n : " << n << endl;
    assert(1<=n && n<=20);
  }

  int sum = 0;
  set<string> s;
  for(int i=0; i<n; i++){
    string tmp;
    cin >> tmp;
    sum += tmp.size();
    for(auto c : tmp){
      assert( 'a' <= c && c <= 'z' );
    }
    s.insert( tmp );
  }

  assert( s.size() == n );
  assert( sum <= 1000 );

  cerr << "all clear" << endl;
  return 0;
}