As part of a beautification activity at Cynthia's junior high school, the students planted flowers in prepared planters. There are two types of planters, small and large. There are 45 planters in total. The students planted 2 salvias and 2 marigolds in the small planters, and 7 salvias in the large planter. The flowers planted in all the prepared planters totaled 231. How many marigolds were planted in the planters?