Salt SLS remove last octect of IP address from grain

I'm trying to match conditions based on the third octet of an IP address since Windows minions don't report the gateway. I can get the grain info for the IP and match the full IP like below but I only want to match to the third octet:

{% set subnet = salt['grains.get']('ipv4:0')  %}
user_coinfig:
  cmd.run:
    {% if subnet == '10.1.244.146' %}
    - name: |
        cmd.exe net localgroup administrators user /add
    {% elif subnet == '10.1.245.146' %}
    - name: |
        cmd.exe net localgroup administrators user /add
    {% endif %}

Desired state:

{% set subnet = salt['grains.get']('ipv4:0')  %}
user_coinfig:
  cmd.run:
    {% if subnet == '10.1.244' %}
    - name: |
        cmd.exe net localgroup administrators user /add
    {% elif subnet == '10.1.245' %}
    - name: |
        cmd.exe net localgroup administrators user /add
    {% endif %}

Since Jinja is a templating language based on Python, you do have access to all of the string methods of Python.
And for this case, you can use the method startswith().

So, you can do:

{% if subnet.startswith('10.1.244.') %}
- name: |
    cmd.exe net localgroup administrators user /add
{% endif %}