library(pacman)
p_load(deSolve)

Lorenz <- function (t, y, parms) {
list(c(y[1]*0.005, 
       y[2]*0.01 + (y[1]*0.1)
      ))
}

ode(y=c(
       S=1850, 
       L=100), 
    times = seq(0,10), func = Lorenz,parms = NULL)