How many people are there in a group of phoenixes spreading their wings in Hongqi Canal?

There are four people in this group.

In the third season of Li Xiang China, Li Lei described the hardships and greatness of the construction of the Hongqi Canal. On the site of Hongqi Canal, there are a group of iron girls. The homework of male migrant workers is to play with a single brazing rod in both hands, and the iron girl can play with a single brazing rod in one hand and a double brazing rod in the other, which doubles the efficiency. Everyone calls this classic homework scene "Phoenix Spreading its Wings".