If all the boxes are arranged in alphabetical order from the top, then how many boxes are unchanged in their position?

Study the following information carefully and answer the below questions Eight boxes – Q, R, S, T, U, V, W and X are kept one above another in the eight different shelves such that the lowermost shelf is numbered as one and the topmost shelf is numbered as eight. All the information is not necessarily in the same order. Box U has kept two shelves above box Q. Box X has kept immediately below box Q and kept at an even number position. The number of shelves above U is the same as the number of shelves below R. Box T has kept two shelves above box W. Box V has kept above Box S. At least three boxes are kept between V and S.