How to install pip3 for python 3.x

I want to install pip3 with the command buf failed:

sudo apt-get install python3-pip

So I try to install it manually.
I have already installed the python3,so firstly I should install the pip

Install pip for python3.x

install the setuptools:

wget --no-check-certificate  https://pypi.python.org/packages/source/s/setuptools/setuptools-19.6.tar.gz#md5=c607dd118eae682c44ed146367a17e26

tar -zxvf setuptools-19.6.tar.gz

cd setuptools-19.6.tar.gz

python3 setup.py build

python3 setup.py install

then install the pip:

wget --no-check-certificate  https://pypi.python.org/packages/source/p/pip/pip-8.0.2.tar.gz#md5=3a73c4188f8dbad6a1e6f6d44d117eeb

tar -zxvf pip-8.0.2.tar.gz

cd pip-8.0.2

python3 setup.py build

python3 setup.py install