A,B = [int(i) for i in input().split()]
if A > B and A-B > 1:
    print(A-B-1+2000000000-A)
elif A > B:
    print(2000000000-A)
elif A < B and B-A>1:
    print(A-1+(B-A-1))
else:
    print(A-1)