pattern matching java
import java.io.*;
import java.util.*;
import java.util.Collections;
import java.util.regex.*;
public class Solution {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int num = scanner.nextInt();
String emailRegEx = ".+@gmail\\.com$";
Pattern pattern = Pattern.compile(emailRegEx);
List<String> list = new ArrayList();
for (int i = 0; i < num; i++){
String name = scanner.next();
String email = scanner.next();
Matcher matcher = pattern.matcher(email);
if (matcher.find()){
list.add(name);
}
}
Collections.sort(list);
for (String name : list){
System.out.println(name);
}
}
}