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

Hi, I need help.

What should i do for fix this error

function dydt = fix_reaksi_tumor_glioma(t,y)
dydt = zeros(size(y));

% Parameter model pertumbuhan glioma (1 g/ml = 10^3 mg/ml)
aT = 1.575; % ml^2 g^-2 day^-1
KT = 2; % g/ml
dTI = 0.072; % day^-1 
aTI = 3*10^-4; % day^-1 
dT = 1*10^-4; % day^-1
dI = 0.01; % day^-1 
as = 0.7; % day^-1 
v = 0.7; % day^-1 
dTo = 1; % day^-1 
ao = 20; % day^-1 
omin = 8.00*10^-4; % g/ml
o0 = 1.6*10^-3; % g/ml
do1 = 0.01; % day^-1
do2 = 0.00625; % day^-1
dTT = 0.72; % day^-1
f_glukosa = omin*sin(6*pi*t); %Asupan glukosa


T = y(1); % pertumbuhan sel glioma (Tumor)
B = y(2); % konsetrasi glukosa dalam otak (obrain)
I = y(3); % aktivitas sistem kekebalan tubuh (imune)
S = y(4); % konsentrasi glukosa dalam serum (oserum)

dydt(1)= aT*B*T*(1-T/KT) - dT*T - dTI*T*I;
dydt(2)= ao*(S-B) - dTo*T*B - (do1+as*(v+I))*B;
dydt(3)= as*(v+I)*B + aTI*T*I - dI*I - dTT*T*I;
dydt(4)= ao*(B-S) + f_glukosa - do2*S; 

dydt=[dydt(1); dydt(2); dydt(3); dydt(4)];

I get error

Error in fix_reaksi_tumor_glioma (line 33)
dydt(4)= ao*(B-S) + f_glukosa - do2*S;
 
K>> dydt(4)= ao*(B-S) + f_glukosa - do2*S;
In an assignment  A(I) = B, the number of elements in B and I
must be the same.