Budget for Eastern Europe Trip

I’m planning a trip for 2 to Hungary, Austria and the Czech Republic with a 1D layover in Finland for a period of 15 days. We’ve pre-booked the flights, accommodation, and Intra-Schengen transfers. Do you think $ 800 should be sufficient for food, activities, and transport for 2 people for 2 weeks? Is it do-able or should I pump up the budget, if so by how much?