import java.util.List;

public class Task1 {
    private <T> void f(List<T> list) {
        if (list.size() > 1) {
            var swap = list.get(0);
            var lastIndex = list.size() - 1;

            list.set(0, list.get(lastIndex));
            list.set(lastIndex, swap);
        }
    }

    public static void main(String[] arguments) {
    }
}