a,b = map(int,input().split())
if a == 0 and b == 0: #0乘任何数都等于0,无限解
print('A')
elif a == 0 and b != 0: #0乘任何数都不等于非0数,无解
print('N')
else:
print('%.2f' % ((0-b)/a)) #ax+b=0 -> ax = -b -> x = -b / a

难点:判断何时方程无解或无限解