ans = 0
x,y,k = int(input()),int(input()),int(input())
ans += 1+((y<0)+(x!=0))

x,y,k = map(abs,(x,y,k))
a,b = x//k,y//k

if a*k!=x:
    a+=1
if b*k!=y:
    b+=1
ans += a + b
print(ans)