import java.util.Collections;

import java.util.HashSet;

import java.util.Set;

public class Main {
public static <T> Set<T> union(final Set<T>... elements) {
return ((elements.length == 0) ? Collections.<T> emptySet()
: new HashSet<T>(elements.length * elements[0].size()) {
private static final long serialVersionUID = -3161916411604210423L;
{
for (final Set<T> s : elements) {
addAll(s);
}
}
});
}
}