AT_abc443_b [ABC443B] Setsubun

At the annual Setsubun festival, one eats the same number of beans as their age. Takahashi-kun does not eat beans at any other time. He is $ N $ years old at this year's Setsubun ( $ 0 $ years later). At the earliest, how many years later will he have eaten a total of $ K $ or more beans from this year onward (including this year)? He is immortal, so he will eventually have eaten a total of $ K $ or more beans from this year onward.

The input is given from Standard Input in the following format: > $ N $ $ K $

Print the answer.

### Sample Explanation 1 - At Setsubun $ 0 $ years later, Takahashi-kun eats $ 4 $ beans, totaling $ 4 $ beans from this year onward. - At Setsubun $ 1 $ year later, he eats $ 5 $ beans, totaling $ 9 $ beans from this year onward. - At Setsubun $ 2 $ years later, he eats $ 6 $ beans, totaling $ 15 $ beans from this year onward. - At Setsubun $ 3 $ years later, he eats $ 7 $ beans, totaling $ 22 $ beans from this year onward. - At Setsubun $ 4 $ years later, he eats $ 8 $ beans, totaling $ 30 $ beans from this year onward. - At Setsubun $ 5 $ years later, he eats $ 9 $ beans, totaling $ 39 $ beans from this year onward. - At Setsubun $ 6 $ years later, he eats $ 10 $ beans, totaling $ 49 $ beans from this year onward. At Setsubun $ 6 $ years later, he will have eaten a total of $ 43 $ or more beans, so output $ 6 $ . ### Sample Explanation 2 The number of beans eaten this year alone may reach $ K $ or more. ### Constraints - All input values are integers. - $ 1 \le N,K \le 10^8 $