[t, X]=ode45(@SI,[0,20],[10000;1;0]);

plot(t,X)
%title ('Ro=0.68') 
xlabel('t'),ylabel('S,I and R')
legend ('Susceptible','Infected', 'Recovered',0)
% subplot(1,3,1), plot(t,X(:,1),'r'),ylabel('Susc city 0')
% subplot(1,3,2), plot(t,X(:,2),'b'), ylabel('Infec city 0')
% subplot(1,3,3), plot(t,X(:,3),'m'), ylabel('Recov city 0')