function dxdt = SIR_model(t,x,par)

S = x(1);
I = x(2);
R = x(3);

beta = par(1);
alpha = par(2);

% % Or, if par is a structure:
% beta = par.beta;
% alpha = par.alpha;

dxdt = zeros(3,1);

dxdt(1) = -beta*S*I;
dxdt(2) = beta*S*I - alpha*I;
dxdt(3) = alpha*I;


end
