Vegetarian Chili In Sweet Potato Boats

• 200 oven for about
• 6 sweet potatoes
• 2 sweet green peppers
• 2 onions
• 2 garlic (cloves)
• 525 gr tomatoes (canned)
• 450 gr black beans (canned)
• 150 gr corn nibblets
• 80 ml yogurt (plain)
• 16 ml olive oil