Four Immeasurables, Sympathetic Joy Part 2

The third immeasurable line starts this way. We have seen sdug bsngal before, it's suffering.

med pa is a form of negation, it means non-existent, absent, free from. This is connected to the first part, sdug bsngal. Notice the 'i at the end of med pa, it means that there is a genitive particle that binds this with the next construct, bde ba.

bde ba is happiness. So when you combine this sequence, it becomes happiness of no suffering.