X,Y,L = input(),input(),input()

if abs(X)%L == 0 and abs(Y)%L == 0:
    A = abs(X)/L+abs(Y)/L
elif abs(X)%L == 0 and abs(Y)%L != 0:
    A = abs(X)/L+abs(Y)/L+1
elif abs(X)%L != 0 and abs(Y)%L == 0:
    A = abs(X)/L+1+abs(Y)/L
else:
    A = abs(X)/L+1+abs(Y)/L+1

if X == 0 and Y >= 0:
    pass
elif X > 0 and Y >= 0:
    A = A + 1
elif X > 0 and Y < 0:
    A = A + 2
elif X < 0 and Y < 0:
    A = A + 2
elif X < 0 and Y >= 0:
    A = A + 1
else:
    pass
print A