import java.util.Scanner; class Question394 { public static void main(String[] str) { Scanner scan = new Scanner(System.in); int score[] = new int[6]; double point = 0; for(int i=0; i<6; i++){ score[i] = scan.nextInt(); } for(int i=1; i<5; i++){ point += score[i]; } System.out.printf("%.2f\n",point/4); } }