class Solution {
    public int findNumbers(int[] nums) {
        return checkEven(nums,0,0);
    }
    public int checkEven(int[] nums,int i,int ans){
        if(i<nums.length){
            int n=0;
            while(nums[i]>0){
                nums[i]/=10;
                n++;
            }
            if(n%2==0){
                ans++;
            }
            return checkEven(nums,i+1,ans);
        }
        return ans;
    }
}