public int group_counter( int[][] board, int group, int value ){
        int row = (SQRT_DIGITS)*(group / SQRT_DIGITS);
        int column = (SQRT_DIGITS)*(group % SQRT_DIGITS);
        int counter = 0;
        for( int i=0; i<SQRT_DIGITS; i++ ){
            for( int j=0; j<SQRT_DIGITS; j++ ){
                if (board[row+i][column+j] == value) {
                    counter++;
                }
            }
        }
        return counter;
    }