public static int conta(s A) {

        int conta = 0;
        boolean f = checkUnival(A,A.val);
        if (f) {
            conta++
        }
        if (A.left != null) {
            conta += conta(A.left);
        }

        if (A.right != null) {
            conta += conta(A.right);
        }


        return conta;
    }

    public static boolean checkUnival(s A, int i) {

        if (A.left == null && A.right == null && A.val == i) {
            return true;
        }

        if (A.val == i) {
            boolean checkLeft = true;
            boolean checkRight = true;

            if (A.left != null) {
                checkLeft = checkUnival(A.left, i);
            }

            if (A.right != null) {
                checkLeft = checkUnival(A.left, i);
            }

            return checkLeft && checkRight;
        }
        else {
            return false;
        }

    }