Share 'et y'en a marre'

I don't have much time to learn French, unfortunately. I try to learn something new every day using  songs and texts that interest me to make it fun. I was translating this song Tous Les Mêmes by Stromae and I wonder why one would say " y'en a marre" who is the subject? "Tous les mêmes, tous les mêmes, tous les mêmes et y'en a marre" Here are some translations for this expression http://dictiona…