Helga went shopping for a new pair of shoes. At the first store, she tried on 7 pairs of shoes. At the second store, she tried on 2 more pairs than at the first store. At the third store, she did not try on any shoes, but she did buy a scarf.  But at the fourth store, she tried on twice as many pairs of shoes as she did at all three other stores combined, before finally choosing a pair to buy.  What is the total number of pairs of shoes Helga tried on before buying her new shoes?
Can you solve this problem?