Feed Pigeons Feed Pigeons
Simple
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I start to feed one of the pigeons. A minute later two more fly by and a minute after that another 3. Then 4, and so on (Ex: 1+2+3+4+...). One portion of food lasts a pigeon for a minute, but in case there's not enough food for all the birds, the pigeons who arrived first ate first. Pigeons are hungry animals and eat without knowing when to stop. If I have N portions of bird feed, how many pigeons will be fed with at least one portion of wheat?

pigeons pigeons

Input: A quantity of portions wheat as a positive integer.

Output: The number of fed pigeons as an integer.

Example:

checkio(1) == 1
checkio(2) == 1
checkio(5) == 3
checkio(10) == 6
    

How it is used: This task illustrates how we can model various situations. Of course, the model has a limited approximation, but often-times we don't need a perfect model.

Precondition: 0 < N < 105.