import math
w,m,n=map(int,input().split())
a=math.ceil(m/w)
b=math.ceil(n/w)
x=abs(a-b)
if a%2!=0:
    x1=m%w
else:
    x1 = w - (m % w) + 1
if b%2!=0:
    x2 = n % w
else:
    x2=w-(n%w)+1
print(x+abs(x1-x2))