public class WithArray {
    public static void main(String[] args) {
        int[] grades = new int[3];
        grades[0] = 5;
        grades[1] = 6;
        grades[2] = 10;
        int sum = 0;
        for (int i = 0; i < grades.length; i++) {
            sum += grades[i];
        }
        double average = ((double) sum) / grades.length;
        System.out.println(average);
    }
}