How to count the number of tourist receptions

If the number of tourists in an area is divided into two types, one is overnight and the other is overnight. How many people spend the night in the local area for a few days? For example, a certain area received 10 people in a certain period of time, and this 10 people spent 10 nights in this area. Then the number of tourists is 10× 10= 100 (person-times). But the overnight stay is only one day, which is not easy to calculate. The standard of calculation is based on the number of tickets sold and the number of tickets for scenic spots. This algorithm has great limitations, but now the country basically uses this method to calculate.