global N beta gamma

t0=0;
tf=300;
N=3.3E8;
NI=1;

Recovery = 14.0;
gamma = 1.0/Recovery;
R0 = 3.45;
beta = R0*gamma;

[t,y]=ode15s('sircovf',[t0,tf],[N-NI,NI,0]);
plot(t,y(:,1),t,y(:,2),t,y(:,3))
xlabel('Time')
ylabel('Populations')
title('SIR Model')
legend('Susceptible','Infected','Recovered')