A classroom has 4 benches. Each one can seat two students. Assume that the benches are numbered 1 to 4 from front to back. Eight students, A, B, C, D, E, F, G and H are sitting on the benches, not necessarily in that order. Following are known: I.  A and G have a gap of two benches between them, so do B and H.  II.  C and E are not sitting on the same bench. III.  D is sitting in front of F, and F is sitting in front of G.