3. In the country, there are 9 cities, some of which are connected by postal flights. To send a letter from one city to another, you need to stick as many stamps on it as the number of flights required (the route with the fewest flights is used). It is known that even if two cities are not connected by a flight, it is always possible to send a letter from one to the other.

Under the New Year, the mayors of all cities sent congratulatory letters to each other. What is the maximum number of stamps they could have needed?
Answer: 240

## Examples of answer recording:

1000

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