public static List<Integer> getMinimumDifference(List<String> a, List<String> b) {
    // Write your code here
        List<Integer> result = new ArrayList<>();
        for(int i=0;i<a.size();i++){
            result.add(countDifference(a.get(i),b.get(i)));
        }
    
        return result;
    }
    public static int countDifference(String s1 , String s2){
        if(s1.length()!=s2.length()){
            return -1;
        }
    int count = 0; 
  
        // store the count of character 
        int char_count[] = new int[26]; 
  
        // iterate though the first String and update  
        // count 
        for (int i = 0; i < s1.length(); i++)  
            char_count[s1.charAt(i) - 'a']++;         
  
        // iterate through the second string 
        // update char_count. 
        // if character is not found in char_count 
        // then increase count 
        for (int i = 0; i < s2.length(); i++)  
            if (char_count[s2.charAt(i) - 'a']-- <= 0) 
                count++; 
          
        return count; 
    }