{ diff(x1, t) = 0,
  diff(x2, t) = 0,
  diff(x3, t) = (1*k5*k25*k73*x11*1/(1 + (x3/k26)^k27) + 1*k5*k28*k74*x11*1/(1 + (x3/k29)^k30) + (-1)*k5*k4*x3/(k59 + x3) + (-1)*k5*k62*k85*x3/(k63 + x3))/k5,
  diff(x4, t) = 0,
  diff(x5, t) = (1*k5*k67*(k6 - k7*x5)/(1 + (x3/(k8/(1 + k68/k9)))^k10) + 1*k5*k69*(k11 - k12*x5)/(1 + (x3/k13)^k14) + 1*k5*k70*(k15 - k16*x5)/(1 + (x9/k17)^k18) + 1*k5*k71*(k19 - k20*x5)/(1 + (x9/k21)^k22) + (-1)*k5*k72*(k23*x5 - k24*x11))/k5,
  diff(x6, t) = 0,
  diff(x7, t) = 0,
  diff(x8, t) = 0,
  diff(x9, t) = (1*k5*x17*x15*(k41 + k42*k68^k44/k43)/(1 + k68^k44/k43)/(k46*(1 + k68/k47)/(1 + k68/k48)/(1 + k68^k44/k49)*(1 + k76/k45) + x15) + (-1)*k5*k80*x9*k54/(1 + (x23/(k55 + k56*k81/(k57 + k81)))^k58) + (-1)*k5*k4*x9/(k60 + x9) + (-1)*k5*k64*k87*x9/(k65 + x9))/k5,
  diff(x10, t) = 0,
  diff(x11, t) = (1*k5*k72*(k23*x5 - k24*x11) + (-1)*k5*k25*k73*x11*1/(1 + (x3/k26)^k27) + (-1)*k5*k28*k74*x11*1/(1 + (x3/k29)^k30) + (-1)*k5*k31*k70*x11*(k32 + k33/(1 + x9/k34)) + (-1)*k5*k35*k71*x11*(k36 + k37/(1 + x9/k38)))/k5,
  diff(x12, t) = 0,
  diff(x13, t) = 0,
  diff(x14, t) = (1*k5*k31*k70*x11*(k32 + k33/(1 + x9/k34)) + 1*k5*k35*k71*x11*(k36 + k37/(1 + x9/k38)) + (-1)*k5*k39*k75*x14/(k40 + x14))/k5,
  diff(x15, t) = (1*k5*k39*k75*x14/(k40 + x14) + (-1)*k5*x17*x15*(k41 + k42*k68^k44/k43)/(1 + k68^k44/k43)/(k46*(1 + k68/k47)/(1 + k68/k48)/(1 + k68^k44/k49)*(1 + k76/k45) + x15) + (-1)*k5*k78*x15*k50/(1 + k51/k77)/(k52/(1 + k51/k77)*(1 + k76/k53) + x15))/k5,
  diff(x16, t) = 0,
  diff(x17, t) = 0/k5,
  diff(x18, t) = 0,
  diff(x19, t) = 0,
  diff(x20, t) = 0,
  diff(x21, t) = 0,
  diff(x22, t) = 0,
  diff(x23, t) = (1*k5*k80*x9*k54/(1 + (x23/(k55 + k56*k81/(k57 + k81)))^k58) + (-1)*k5*k4*x23/(k61 + x23))/k5,
  diff(x24, t) = 0,
  diff(x25, t) = 0,
  diff(x26, t) = 0,
  diff(x27, t) = 0,
  diff(x28, t) = 0,
  diff(x29, t) = 0,
  diff(x30, t) = 0,
  diff(x31, t) = 0 }