function xprime=input_multivessel(t,X) 
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%%%%% Program written by Stathis skouras, May 2001. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% Number of stages in the top section: 
NT1=25;
% Number of stages in the bottom section (without the reboiler): 
NT2=25;
% Total number of 'stages'  
NT=NT1+NT2+3;  % We include condenser and middle vessel (for practical reasons) and reboiler 

% Inputs
VB=5;                                  % Boilup (kmol/hr)
L0=VB;                                 % Nominal liquid flows in both sections of the column (kmol/hr)

% Store all inputs and disturbances
U(1)=VB; U(2)=L0;
xprime=multivessel(t,X,U);
t