Growing Sequences
시간 제한1초메모리 제한2048 MB
각 원소가 1 이상 c 이하이고 이전 원소의 두 배 이상인 길이 n 배열의 개수를 998244353으로 나눈 나머지를 구한다.
문제
In scientific research, exponentially growing sequences appear quite often. Some researches are especially interested in integer arrays of length where each element is at least twice as large as the previous one: formally, for . They want to calculate the number of different bounded arrays satisfying this condition.
Help them! Count the number of such arrays consisting of integers from to . Since this number can be very large, you should output it modulo .
입력
The only line contains two integers and (; ): the length of the arrays and the maximum value of their elements.
출력
Output the number of different arrays modulo .
힌트
In the first example, there are different arrays: , , , , .
In the second example, there are different arrays: , , , .
In the third example, there are no arrays satisfying the conditions.