def distance(k):
    b=abs(k)
    if b%L==0:
        return b//L
    else:
        return b//L+1
x=int(input())
y=int(input())
L=int(input())
if x!=0 and y!=0:
    print(1+distance(x)+distance(y))
elif x==0 and y==0:
    print(0)
elif x!=0 and y==0:
    print(distance(x))
elif x==0 and y!=0:
    print(distance(y))