Chemistry

Problem

Consider the following table

Total number of electron pairs<br>(l.p. + $\sigma$ -bond)	Total number of<br>lone pairs	Shape
5	.....p.....	linear
.....q.....	1	see-saw
4	.....r.....	Bent shape
.....s.....	2	Square planar
5	.....t.....	Bent 'T' shape

Then calculate value of "

p + q + r - s - t