lambda=input('enter arrival rate');
mu=40;
if lambda>=mu
disp('the system is unstable');
else
    rho=lambda/mu;
    Ls=lambda/(mu-lambda);
    Lq=lambda^2/(mu*(mu-lambda));
    Wq=lambda/(mu*(mu-lambda));
    Ws=1/(mu-lambda);
    disp('average number of trains in system :');
    disp(Ls);
    disp('average number of trains in queue :');
    disp(Lq);
    disp('mean waiting time in queue :');
    disp(Wq);
    disp('mean waiting time in system :');
    disp(Ws);
    end