The Zios have 3 legs and the Zepts have 7 legs.

The great planetary explorer Nico, who first discovered the planet, saw a crowd of Zios and Zepts.

He managed to see that there was more than one of each creature before they saw him and all rolled onto their backs and put their legs in the air.

He counted 52 legs.

How many Zios and how many Zepts were there altogether?