M,N = map(int, input().split())

if N == 0:
    print(M)
else:
    dp = [[0]*3 for _ in range(N)]
    dp[0][0] = 2*M
    dp[0][1] = M+1
    for i in range(N-1):
        dp[i+1][0] = sum(dp[i])*2/3
        dp[i+1][1] = sum(dp[i])/3 + 1

    print(sum(dp[N-1])/3)