Hello, I Did Unprotected Sex With My Wife Yesterday Night

Hello, i did unprotected sex with my wife yesterday night at 12. Her last menstrual period was july, 8. Her period is regular every 32 days. I gave her 4 tablets of marvelon after 10 hours of intercourse and will give her the rest 4 tablets after 12 hours.bhow is her risk for unwanted pregnancy?thank you so much