How many persons are sitting between P and W ?

The data given to us is:
P, Q, R, S, T, V and W are sitting in a straight line facing north but not necessarily in the same order. R sits third to the left of W. Neither R nor W sits at extreme ends of the line. Only one person sits between R and T. S is not an immediate neighbour of either R or W.Two people sit between T and P. Q is an immediate neighbour of S..

This data can be represented in diagrammatic form as:

Three people are sitting between P and W.