{ diff(x1, t) = (1*k64*k8*k65^k62/(k65^k62 + x19^k62) + (-1)*k64*k10*x1 + (-1)*k64*k9*x1/(k21 + x1))/k64,
  diff(x2, t) = (1*k64*k37*x1 + (-1)*k64*k38*x2/(k22 + x2) + (-1)*k64*(k40*x2 - k41*x4) + (-1)*k64*k16*x2 + 1*k64*k39*x3/(k23 + x3))/k64,
  diff(x3, t) = (1*k64*k38*x2/(k22 + x2) + (-1)*k64*k16*x3 + (-1)*k64*k42*x3/(k26 + x3) + (-1)*k64*k39*x3/(k23 + x3))/k64,
  diff(x4, t) = (1*k64*(k40*x2 - k41*x4) + (-1)*k64*(k33*x13*x4 - k34*x16) + (-1)*k64*k43*x4/(k22 + x4) + (-1)*k64*k16*x4 + 1*k64*k44*x14/(k23 + x14))/k64,
  diff(x5, t) = (1*k64*k17*x6 + (-1)*k64*k18*x5/(k22 + x5) + (-1)*k64*(k15*x5*x9 - k14*x11) + (-1)*k64*k20*x5 + 1*k64*k19*x7/(k23 + x7))/k64,
  diff(x6, t) = ((-1)*k64*k7*x6 + 1*k64*k5*x4^k63/(k58^k63 + x4^k63) + (-1)*k64*k6*x6/(k60 + x6))/k64,
  diff(x7, t) = (1*k64*k18*x5/(k22 + x5) + (-1)*k64*k25*x7/(k26 + x7) + (-1)*k64*k16*x7 + (-1)*k64*k19*x7/(k23 + x7))/k64,
  diff(x8, t) = (1*k64*(12/5 + (3 - 12/5)*ceiling(sin(pi*t/12 + 1/1000)/2))*x4^k63/(k57^k63 + x4^k63) + (-1)*k64*k4*x8 + (-1)*k64*k3*x8/(k59 + x8))/k64,
  diff(x9, t) = (1*k64*k11*x8 + (-1)*k64*k12*x9/(k22 + x9) + (-1)*k64*(k15*x5*x9 - k14*x11) + (-1)*k64*k16*x9 + 1*k64*k13*x10/(k23 + x10))/k64,
  diff(x10, t) = ((-1)*k64*k24*x10/(k26 + x10) + 1*k64*k12*x9/(k22 + x9) + (-1)*k64*k16*x10 + (-1)*k64*k13*x10/(k23 + x10))/k64,
  diff(x11, t) = (1*k64*(k15*x5*x9 - k14*x11) + (-1)*k64*k27*x11/(k22 + x11) + (-1)*k64*(k30*x11 - k29*x13) + (-1)*k64*k16*x11 + 1*k64*k28*x12/(k23 + x12))/k64,
  diff(x12, t) = (1*k64*k27*x11/(k22 + x11) + (-1)*k64*k35*x12/(k26 + x12) + (-1)*k64*k16*x12 + (-1)*k64*k28*x12/(k23 + x12))/k64,
  diff(x13, t) = (1*k64*(k30*x11 - k29*x13) + (-1)*k64*k31*x13/(k22 + x13) + (-1)*k64*(k33*x13*x4 - k34*x16) + 1*k64*k32*x15/(k23 + x15) + (-1)*k64*k16*x13)/k64,
  diff(x14, t) = ((-1)*k64*k16*x14 + 1*k64*k43*x4/(k22 + x4) + (-1)*k64*k45*x14/(k26 + x14) + (-1)*k64*k44*x14/(k23 + x14))/k64,
  diff(x15, t) = ((-1)*k64*k16*x15 + 1*k64*k31*x13/(k22 + x13) + (-1)*k64*k36*x15/(k26 + x15) + (-1)*k64*k32*x15/(k23 + x15))/k64,
  diff(x16, t) = (1*k64*(k33*x13*x4 - k34*x16) + (-1)*k64*k16*x16 + (-1)*k64*k46*x16/(k26 + x16))/k64,
  diff(x17, t) = (1*k64*k47*x4^k61/(k48^k61 + x4^k61) + (-1)*k64*k51*x17 + (-1)*k64*k49*x17/(k50 + x17))/k64,
  diff(x18, t) = (1*k64*k52*x17 + (-1)*k64*(k53*x18 - k54*x19) + (-1)*k64*k55*x18/(k26 + x18) + (-1)*k64*k16*x18)/k64,
  diff(x19, t) = (1*k64*(k53*x18 - k54*x19) + (-1)*k64*k56*x19/(k26 + x19) + (-1)*k64*k16*x19)/k64 }