You are given an array `nums`

of non-negative integers. `nums`

is considered **special** if there exists a number `x`

such that there are **exactly** `x`

numbers in `nums`

that are **greater than or equal to** `x`

.

Notice that `x`

**does not** have to be an element in `nums`

.

Return `x`

*if the array is special, otherwise, return *

`-1`

. It can be proven that if `nums`

is special, the value for `x`

is

**Example 1:**

Input:nums = [3,5]Output:2Explanation:There are 2 values (3 and 5) that are greater than or equal to 2.

**Example 2:**

Input:nums = [0,0]Output:-1Explanation:No numbers fit the criteria for x. If x = 0, there should be 0 numbers >= x, but there are 2. If x = 1, there should be 1 number >= x, but there are 0. If x = 2, there should be 2 numbers >= x, but there are 0. x cannot be greater since there are only 2 numbers in nums.

**Example 3:**

Input:nums = [0,4,3,0,4]Output:3Explanation:There are 3 values that are greater than or equal to 3.

**Example 4:**

Input:nums = [3,6,7,7,0]Output:-1

**Constraints:**

`1 <= nums.length <= 100`

`0 <= nums[i] <= 1000`

class Solution {
public int specialArray(int[] nums) {
}
}