n0
900
m0
400
r1
0.02
r2
0.01
k1
2000
k2
3000
a12
1
a21
1












nt
n0
nt+r1*nt*(k1-nt-a12*mt)/k1
mt
m0
mt+r2*mt*(k2-mt-a21*nt)/k2