import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
"""
x = (n - 1) / 2

2 * x == (n - 1) (mod b)

"""

n, b = na()

if n % 2 == 1:
    print(((n - 1) // 2) % b)
elif b % 2 == 1:
    print((n - 1) * pow(2, -1, b) % b)
else:
    print("NaN")