Five friends, Sandya, Rinku, Prachi, Thiru and Madavi, are sitting on a bench in a playground, facing north (but not necessarily in the same order). Sandya is to the immediate left of Rinku and to the immediate right of Prachi. Madavi is somewhere to the right of Rinku. Thiru is an immediate neighbour of both Rinku and Madavi.

Who is sitting at the rightmost end?