General Intelligence · Puzzle

Seven boxes, A, B, C, D, E, F and G, are kept one over the other but not necessarily in the same order. Only three boxes are kept above F. Only one box is kept between D and F. Only three boxes are kept between D and B. B is kept at some place above F. G is kept immediately below B. E is kept at one of the places above A. C is not kept immediately above or be low D. How many boxes are kept above G?