Five friends Priyanka, Mrinalini, Gitanjali, Arnav and Shivalika travelled in different months of the same year viz. January, July, August, September and December. Gitanjali was the first one to travel in the year. Mrinalini travelled in the month immediately after Priyanka. Arnav travelled in the month immediately before Shivalika who was the last one to travel in the year. Who travelled in the month of August?