param alpha = 0.005
param delta = 0.2
param beta = 1.0
param gamma = 0.02
param N0 = 100
param P0 = 100

state N = N0
state P = P0

N' = beta*N - gamma*N*P
P' = alpha*N*P - delta*P

print t, N, P
plot t, N, P
plot N, P

option tstart=0, tstop=300