X = int(input())
Y = int(input())
L = int(input())

def distance(x,y,L):
    if abs(x) % L == 0:
        a = abs(x) // L
    else:
        a = (abs(x) // L)+1
    if abs(y) % L == 0:
        b = abs(y) // L
    else:
        b = (abs(y) // L)+1    
    return int(a+b)    

if X > 0 and Y > 0 :
    print( 1  + distance(X,Y,L))
if X > 0 and Y < 0 :
    print( 2 + distance(X,Y,L)) 
if X < 0 and Y > 0:
    print( 1 +distance(X,Y,L))    
if X < 0 and Y < 0:
    print( 3 +distance(X,Y,L))    
if X == 0 :
    if Y > 0 :
        print(int(Y//L))
    if Y < 0 :
        print( 2 + int(abs(Y)//L))
if Y == 0:
    if X > 0 :
        print(int(X//L))
    if X < 0 :
        print( 2 + int(abs(X)//L))   
if X == 0 and Y == 0:
    print(0)