How can I make a simple counter with Jinja2 templates?

I have two for loops, both alike in dignity. I'd like to have a counter incremented during each inner iteration.

For example, consider this template:

from jinja2 import Template

print Template("""
{% set count = 0 -%}
{% for i in 'a', 'b', 'c' -%}
  {% for j in 'x', 'y', 'z' -%}
    i={{i}}, j={{j}}, count={{count}}
    {% set count = count + 1 -%}
  {% endfor -%}
{% endfor -%}
""").render()

Shouldn't this print count=0 through count=8? Nope, it doesn't.

i=a, j=x, count=0
i=a, j=y, count=1
i=a, j=z, count=2
i=b, j=x, count=0
i=b, j=y, count=1
i=b, j=z, count=2
i=c, j=x, count=0
i=c, j=y, count=1
i=c, j=z, count=2

What gives?

Note: I can't simply save the outer loop variable to calculate the counter because, in my software, the number of inner iterations is variable.