How to Prevent n From Going Below 0

So I had to write a script that simulated bacteria growth over a certain number of generations. I've got it all working expect for the fact that I want the program to end if the population drops below 0, as an extinct population can hardly come back suddenly or continue to lose members. Here's the coding, how can I end the program in this situation?

g = input('Number of Generations: ');
n = 1;
p = rand(g);
for a = 1:g
    if p(a) >= 0.5
        n = n + 1;
    elseif p(a) < 0.5
        n = n - 1;
    elseif n == 0
        return;
    end
end
n

Thank you!

Answer 1

[KSSV]

use break if the value of n is 0.

[Gregory Shoemake]

Thank you!