Calculate the number 8340

A Doctor was addressing a large audience. "The material we put into our stomachs is enough to have killed most of us sitting here, years ago.
Red meat is awful. Soft drinks corrode your stomach lining. Chinese food is loaded with MSG. High fat diets can be disastrous, and none of us realizes the long-term harm caused by the germs in our drinking water. But there is one thing that is the most dangerous of all and we all have, or will, eat it. Can anyone here tell me what food it is that causes the most grief and suffering for years after eating it?"
After several seconds of quiet, a 75-year-old man in the front row raised his hand, and softly said, "Wedding Cake."