concatenating matrices of a cell vertically

i have a cell(1,n)=A of matrices (, the matrices have the same number of colums , and different number of rows . i want to concatenate all the matrices in the cell vertically using cat(1,M1,M2). i tried the following code ,but it doesn't work

 for i=2:n
    B(i-1)=cat(1,A{i-1},A{i});
 end
 B(:)

the following error appears

 Error while evaluating uicontrol Callback

 In an assignment  A(I) = B, the number of elements in B and I
 must be the same.

 Error in Spro>export_button_Callback (line 1163)
      B(i-1)=cat(1,A{i-1},A{i});

 Error in gui_mainfcn (line 96)
        feval(varargin{:});

 Error in Spro (line 42)
    gui_mainfcn(gui_State, varargin{:});

 Error in
 @(hObject,eventdata)Spro('export_button_Callback',hObject,eventdata,guidata(hObject))

 Error while evaluating uicontrol Callback

Answer 1

[Image Analyst]

What about this:

A = {ones(4,1),ones(5,1),ones(4,1),ones(5,1)}
allACells = cell2mat(A')

[Elia]

thank you very much