public int countPoints(String rings) {
        int n = rings.length()/2;
        int arr1[] = new int[10];
        int arr2[] = new int[10];
        int arr3[] = new int[10];
        int count = 0;
        
        for(int i=0; i<n; i++){
            if(rings.charAt(2*i) == 'R')
                arr1[rings.charAt(2*i+1)-'0']++;
            if(rings.charAt(2*i) == 'G')
                arr2[rings.charAt(2*i+1)-'0']++;
            if(rings.charAt(2*i) == 'B')
                arr3[rings.charAt(2*i+1)-'0']++;
        }
        
        for(int i=0; i<10; i++){
            if(arr1[i]*arr2[i]*arr3[i] != 0)
                count++;
        }
        
        return count;
    }