import java.util.Scanner;
import java.util.Iterator;
import java.io.*;

public class Lines implements Iterator<String>, Iterable<String> {
    private Scanner scanner;
    public Lines(Scanner scanner) {
        this.scanner = scanner;
    }
    // Implement the iterator and iterable interfaces...
   
    public static void main(String[] args) {
        // Get filename and search string from stdin
        // ...

        // Output every line in the file which contains the search string
        // ...
    }
}