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

dx = abs(X)
dy = abs(Y)

C = (dx // L) + (dy // L)
if dx % L != 0: C += 1
if dy % L != 0: C += 1

turns = 0
if dx != 0 and dy != 0:
    turns = 1  
elif dx != 0 and dy == 0:
    turns = 1  
elif dx == 0 and dy != 0:
    turns = 0  
C += turns
print(C)