3. Petya went to the store for two days in a row and both times he bought buns for exactly 56 rubles. At the same time, on the second day, a bun cost one ruble more than on the first day. Buns always cost a whole number of rubles.

How many buns did Petya buy over the two days? If there are several possible options, list them in any order, separated by a semicolon.

Examples of answer formats:

10

$10 ; 20$
Answer: $84 ; 15$ || $84 ; 15 ;\|84,15\| 15 ; 84\|15,84\| 15 ; 84 ;$