시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
1 초 128 MB 7 5 5 100.000%

문제

Given is an alphabet {0, 1, ... , k}, 0 <= k <= 9 . We say that a word of length n over this alphabet is tight if any two neighbour digits in the word do not differ by more than 1.

입력

Input is a sequence of lines, each line contains two integer numbers k and n, 1 <= n <= 100

출력

For each line of input, output the percentage of tight words of length n over the alphabet {0, 1, ... , k} with 5 fractional digits.

예제 입력

4 1
2 5
3 5
8 7

예제 출력

100.00000
40.74074
17.38281
0.10130

힌트