x = int(input())
y = int(input())
l = int(input())

dir_cnt = 0
if y >= 0:
    if x == 0:
        dir_cnt = 0
    else:
        dir_cnt = 1
else:
    dir_cnt = 2
    
x_move = 0
if x == 0:
    x_move = 0
elif abs(x) // l == 0:
    x_move += 1
elif abs(x) % l != 0:
    x_move += abs(x) // l + 1
else:
    x_move += abs(x) // l
    
y_move = 0
if y == 0:
    y_move = 0
elif abs(y) // l == 0:
    y_move += 1
elif abs(y) % l != 0:
    y_move += abs(y) // l + 1
else:
    y_move += abs(y) // l
    
res = dir_cnt + x_move + y_move

print(res)