Need help interpreting this spectra please

Assignment says to "Interpret the spectra by providing the key stretching frequencies and stating what functional groups they correspond to."

The hint we were given: Look at the PRODUCT and identify the peak that corresponds to the functional group in the molecule. Hint - It is the big peak.

Note: This is a Diels-Alder Reaction

N-phenylmaleide is the dienophile and limiting reagent.

2,3-dimethyl-1,3-butadiene is the diene and reagent in excess.

5,6-dimethyl-2- phenyl-2,3,3a,4,7,7ahexahydro-1Hisoindole-1,3-dione is the product.

5,6-dimethyl-2-phenyl-2,3,3a,4,7,7ahexahydro-1Hisoindole-1,3-dione 5,6-dimethyl-2-phenyl-2,3,3a,4,7,7ahexahydro- 1H-isoindole-1,3-dione