Pizza Potatoes

1 pkg. instant scalloped potatoes
1 16 oz. can tomatoes
1 1/2 cups water
1/4 tsp. crushed oregano
1 4 oz. pkg. sliced pepperoni
1 4 oz. pkg. shredded mozzarella cheese

Heat oven to 400.  Empty potato mix into 2 qt. dish.  Heat tomatoes water and oregano to boiling.  Stir into potato mix. Arrange pepperoni slices on top and sprinkle cheese on top. Bake uncovered for 30-35 minutes.