You are an AI assistant tasked with analyzing a passage of text to insert retrieval tokens and identify Prefix-intent (PI) and Key Factual Information (KFI). A Prefix-Intent (PI) should be a piece of text that should precede factual information, it must not be only 1 or 2 words. Key Factual Information (KFI) should be meaningful and include important details.

Your goal is to insert a  <|retrieval|> token after it is clear what the intent of the text is (e.g., "The president of the USA is"), but  before the key factual information is stated (e.g., "Joe Biden"). Whenever there is a <|retrieval|> token, we will retrieve the key factual information.

Here is the passage you will be working with:

<passage>
Rex-Acme Rex, Rex Motorcycles, Rex-Acme, was a car and motorcycle company which began in Birmingham, England in 1900. Rex soon merged with a Coventry maker of bicycles and cars named Allard and then later in 1922 the company merged with Coventry's 'Acme' motorcycle company forming 'Rex Acme'. The company existed until 1933, and, in its heyday, was considered one of the greatest names in the British motorcycle industry. History Originally, Rex Motorcycles was founded in Birmingham by brothers William and Harold Williamson in 1899, merged with Allard, a Coventry bicycle maker, in 1902, the name remaining Rex. They enlarged the factory, and produced a range of three and four wheel cars (and their first motorcycle). In 1904 they began making motorcycles. The founders were fired by the company in 1911. In 1919 Coventry Acme was taken over, and in 1922 the two companies were amalgamated to form Rex-Acme. Wal Handley then raced Rex-Acme motorcycles, making them famous, and even became a company director, but left in 1928 to ride different machinery. Handley rode Blackburne 173 cc singles, and, in 1926, ohv 498 cc V twins. The name began to fade, and in 1932 was taken over by side-car manufacturers, Mills-Fullford, who ceased manufacture of Rex-Acme motorcycles in 1933. Other famous motorcycle racers that rode Rex-Acme motorcycles were H. G. Tyrell Smith, Arthur Taylor, Charles Needham, Hans Hasenauer, Felice Bonetto, Karl Machu and Otto Cecconi. Rex (1903 - 1922) Around 1903 Rex produced motorcycles with engines above and driving, the front wheel. (the Werner engine position). The engines were Rex’s own, and included singles and V twins. In 1904 there was a 372 cc model which had the silencer cast with the cylinder in one piece. In 1905 the side valve Rex model was rated at 3.25 hp. When they stopped producing these, they used Blackburne engines of 532 cc and 896 cc with Roc patent gear hubs. When the company fired the founders in 1911, George Hemingway had in house engines made again, but models with other engines were still built. Rex made their first telescopic forks in 1906, used rotary-valve engines, and in 1908 were the first to put a downward angle on the top tube, lowering the riding position. In 1914 there was a 349 cc two stroke and 940 cc V twins. After the First World War, the first bike, a 550 cc sv single, was soon dropped in favour of new Blackburne engined machines. These had a longer wheelbase sidecar version available. The singles now had 499 cc, the V twins 998 cc. Rex Acme (1922 - 1933) In the years that followed Rex-Acme motorcycles used engines from 173 cc to 746 cc. There were sv and ohv Blackburne engines, sv JAP engines and also a sleeve valve 348 cc Barr & Stroud. In 1928 there was a 346 cc ohv MAG engined model. The 1929 Rex-Acme range consisted of 346 cc ohv models with two JAP versions, one with 74 mm bore x 80 mm stroke and the other with 70 mm bore x 90 mm stroke; also available as double port engines; 746 cc JAP engined V twin; 496 cc sv singles with JAP or Blackburne engines; 300 cc sv singles with cheaper frames and JAP or Blackburne engines and also similar 346 cc versions., the Speed King with 346 cc Blackburne ohv engines in two versions; and also two versions of a 496 cc Blackburne engined ohv single. There was also a 172 cc Villiers engined super sports model. In the following years, Rex-Acme also fitted MAG and Sturmey-Archer engines. See also Williamson
</passage>

Follow these steps to complete the task:

1. Inserting retrieval tokens:
   a. Read through the text carefully.
   b. Identify potential Prefix-Intent (PI) sections that consist of a single intent and could serve as a search query. You must not modify the prefix intent and it MUST be part verbatim in the passage. It cannot be single or only a few words.
   c. For each identified PI, evaluate if the following sentence/subsentece that could serve as Key Factual Information (KFI).
   d. Insert <|retrieval|> tokens into the text AFTER the Prefix Intent (PI) and BEFORE key factual information is stated (KFI).
   e. Key Factual information should not intersect with Prefix Intent.

2. Identifying Prefix-Intent (PI) and Key Factual Information (KFI):
   a. For each <|retrieval|> token you've inserted, identify the preceding text as the Prefix-Intent (PI).
   b. Identify the following text, up to the next PI, as the Key Factual Information (KFI).
   c. Ensure that both PI and FI are short subsentences or phrases but not 1 or 2 words.

3. Insert <|start-PI|>,<|end-PI|>, <|start-KFI|>, <|end-KFI|>.
   a. For each identified Prefix Intent (PI), add a start and end special tokens (<|start-PI|>,<|end-PI|>) to quickly identify them.
   b. Do the same for the Key Factual Information (KFI) (<|start-KFI|>, <|end-KFI|>)
   c. Ensure that the very first PI in the passage is preceded by <|start-PI|>.
   d. Double-check that every PI and KFI is properly enclosed in these tags.

4. Describing ideal retrieved information:
   a. Given the Prefix-Intent (PI) and Key Factual Information (KFI), imagine an ideal retriever and enormous corpus. 
   b. Using the retriever and corpus, imagine that you can retrieve information given the Prefix-Intent.  
   c. Describe how that content should look like so it helps generating the Key Factual Information (KFI)


5. Reformulate the Prefix Intent if necessary: Reformulate it to not be impersonal. This means that if the subject it is not identified (e.g. it, he, she) you need to add the appropriate subject so the prefix-intent can be understood by itself. The subject should be changed from the previous information in the passage. Reformulated Prefix should not add any extra information or intent that is not mentioned in the original Prefix Intent.


6. Output format:
   For each pair of Prefix-Intent (PI) and Key Factual Information (KFI) you identify, provide the following output separating each example in a JSON list output. Ensure that it is actually a JSON.

   - Prefix_intent: [Write the Prefix Intent here]
   - Prefix_reformulated: [Write the Prefix Intent reformulated]
   - Key_Factual_Information: [Write the Key Factual Information here]
   - Verification: [Confirm that the KFI can be directly derived from the PI given a strictly connected context]
   - Ideal_Knowledge: [Describe how the ideal retrieved content should look to generate the KFI]
   - Explanation: [Briefly explain how the PI and KFI connect and why you chose to insert the <|retrieval|> token in that position]


7. Final step:
   After you have completed the analysis and provided outputs for all identified PI-KFI pairs, present the original passage with the <|retrieval|> tokens inserted in their appropriate positions

Here's an example of the expected output format:

Passage: Girmal Falls General This waterfall extends to a height of up to 100 feet, making it the highest waterfall of Gujarat. The picturesque beauty of this site makes it popular among visitors and people of the region alike. The water swiftly falls from a great height, creating a fog like condition that’s eye catching. The government of this state is working on many projects to make this place an ideal picnic spot and a tourist attraction. The fall comes to its best form at the time of monsoon and provides an immensely striking appearance. Some of the best natural features of Gujarat can be explored in this place. This place is a nice and refreshing retreat for any traveler.

```json
{ "results" : [
  {
    "Prefix_intent": "Girmal Falls General This waterfall extends to a height of up to",
    "Prefix_reformulated": "What is the height of Girmal Falls?",
    "Key_Factual_Information": "100 feet, making it the highest waterfall of Gujarat",
    "Verification": "The KFI directly provides the height information requested in the PI.",
    "Ideal_Knowledge": "A list of waterfalls in Gujarat, India, with their heights and rankings, specifically mentioning Girmal Falls as the highest at 100 feet.",
    "Explanation": "The PI introduces Girmal Falls and sets up a query about its height, while the KFI provides the specific measurement and its significance. The <|retrieval|> token is inserted to indicate where additional information might be needed to support the factual statement."
  },
  {
    "Prefix_intent": "The water swiftly falls from a great height, creating",
    "Prefix_reformulated": "What does the water falling from Girmal Falls create?",
    "Key_Factual_Information": "a fog like condition that's eye catching",
    "Verification": "The KFI directly describes the effect created by the falling water, as prompted by the PI.",
    "Ideal_Knowledge": "Detailed descriptions of the visual effects created by high waterfalls, including the formation of mist or fog-like conditions due to water droplets in the air.",
    "Explanation": "The PI describes the water falling and sets up a query about its effect, while the KFI provides the specific visual phenomenon created. The <|retrieval|> token is inserted to indicate where additional information might be needed to support the description."
  },
  {
    "Prefix_intent": "The fall comes to its best form at the time of",
    "Prefix_reformulated": "When does Girmal Falls come to its best form?",
    "Key_Factual_Information": "monsoon and provides an immensely striking appearance",
    "Verification": "The KFI directly answers when the waterfall is at its best and describes its appearance, as prompted by the PI.",
    "Ideal_Knowledge": "Information on the seasonal variations of Girmal Falls, highlighting the monsoon season's impact on water flow and visual appeal.",
    "Explanation": "The PI sets up a query about the best time to view the falls, and the KFI provides the specific season and describes the appearance. The <|retrieval|> token is inserted to indicate where additional information about seasonal changes might be needed."
  }],
"Updated_Passage":"<|start-PI|> Girmal Falls General This waterfall extends to a height of up to <|end-PI|> <|retrieval|> <|start-KFI|> 100 feet, making it the highest waterfall of Gujarat <|end-KFI|>. The picturesque beauty of this site makes it popular among visitors and people of the region alike. <|start-PI|> The water swiftly falls from a great height, creating <|end-PI|> <|retrieval|> <|start-KFI|> a fog like condition that’s eye catching <|end-KFI|>. The government of this state is working on many projects to make this place an ideal picnic spot and a tourist attraction. <|start-PI|> The fall comes to its best form at the time of <|end-PI|> <|retrieval|> <|start-KFI|> monsoon and provides an immensely striking appearance <|end-KFI|>. Some of the best natural features of Gujarat can be explored in this place. This place is a nice and refreshing retreat for any traveler."
}

```
8. Final check:
  a. Review the Updated_Passage to ensure all PIs and KFIs are properly tagged.
  b. Verify that the first PI in the passage starts with <|start-PI|>.
  c. Make sure there are no missing or misplaced tags.
 
Remember to analyze the entire passage, identify all relevant PI-KFI pairs, and provide the output for each pair as specified. After completing the analysis, present the original passage with the <|retrieval|> tokens inserted in their appropriate positions as part of a new key in the JSON file. Only Ouput the JSON File.