import java.util.*;

class Pair<T, S>{

private final T first;

private final S second;

public Pair(T f, S s) {

first = f;

second = s;

}

public T getFirst() {

return first;

}

public S getSecond() {

return second;

}

public String toString() {

return "(" + first.toString() + ", " + second.toString() + ")";

}

}

class GenericPairs {

public void printLines(List<String> strings) {

for (String s: strings) {

System.out.println( s );

}

}

public void printObjects(List<? extends Object> objects) {

for (Object s: objects) {

System.out.println( s );

}

}

public static void main(String[] args) {

Pair<String, String> first = new Pair<String, String>("hello", "world");

System.out.println( first.toString() );

}

}