import math

def compute_X1(K):
    if K == 1:
        return 0.75
    else:
        return 0.0  # 仅示例，需正确计算

def compute_X2(K):
    if K == 2:
        return 0.644934033
    else:
        return 0.0  # 仅示例，需正确计算

X, K = map(int, input().split())

if X == 1:
    result = compute_X1(K)
else:
    result = compute_X2(K)

print("{0:.9f}".format(result))