Serbian Bean Soup

Ingredients

• 3 (16 ounce) cans green beans (You can also use white beans)
• 3 large potatoes, chopped
• 2 carrots, chopped
• 1/4 cup tomatoes, chopped
• 1/2 cup celery, chopped
• 4 cups water
• 1 onion, chopped
• 3 1/2 tablespoons oil
• 3 tablespoons flour
• salt, to taste
• pepper, to taste