{ diff(x1, t) = 0,
  diff(x2, t) = 0,
  diff(x3, t) = 0,
  diff(x4, t) = (1*k1*(k2*k68/k3*k69/k4 - k5*k70/k6*x4/k7)/((1 + k68/k3 + k70/k6)*(1 + k69/k4 + x4/k7)) + (-1)*k1*(k8*x4/k9 - k10*x5/k11)/(1 + x4/k9 + x5/k11))/k1,
  diff(x5, t) = (1*k1*(k8*x4/k9 - k10*x5/k11)/(1 + x4/k9 + x5/k11) + (-1)*k1*(k12*x5/k13 - k14*x6/k15)/(1 + x5/k13 + x6/k15) + (-1)*k1*(k16*x5/k17 - k18*x6/k19)/(1 + x5/k17 + x6/k19) + (-1)*k1*(k44*x5/k45 - k46*x8/k47*x12/k48)/(1 + x5/k45 + x8/k47 + x12/k48 + x5/k45*x8/k47 + x8/k47*x12/k48) + (-1)*k1*(k49*x5/k50 - k51*x8/k52*x12/k53)/(1 + x5/k50 + x8/k52 + x12/k53 + x5/k50*x8/k52 + x8/k52*x12/k53))/k1,
  diff(x6, t) = (1*k1*(k12*x5/k13 - k14*x6/k15)/(1 + x5/k13 + x6/k15) + 1*k1*(k16*x5/k17 - k18*x6/k19)/(1 + x5/k17 + x6/k19) + (-1)*k1*(k20*x6/k21 - k22*x7/k23)/(1 + x6/k21 + x7/k23) + (-1)*k1*341/10000*((k60*x5/k61 - k62*x6/k63)/(1 + x5/k61 + x6/k63) + (k64*x5/k65 - k66*x6/k67)/(1 + x5/k65 + x6/k67)))/k1,
  diff(x7, t) = (1*k1*(k20*x6/k21 - k22*x7/k23)/(1 + x6/k21 + x7/k23) + (-1)*k1*(k24*x7/k25 - k26*x8/k27)/(1 + x7/k25 + x8/k27))/k1,
  diff(x8, t) = (1*k1*(k24*x7/k25 - k26*x8/k27)/(1 + x7/k25 + x8/k27) + 1*k1*(k28*x9/k29 - k30*x8/k31)/(1 + x9/k29 + x8/k31) + (-1)*k1*(k32*x8/k33 - k34*x10/k35)/(1 + x8/k33 + x10/k35) + 1*k1*(k44*x5/k45 - k46*x8/k47*x12/k48)/(1 + x5/k45 + x8/k47 + x12/k48 + x5/k45*x8/k47 + x8/k47*x12/k48) + 1*k1*(k49*x5/k50 - k51*x8/k52*x12/k53)/(1 + x5/k50 + x8/k52 + x12/k53 + x5/k50*x8/k52 + x8/k52*x12/k53))/k1,
  diff(x9, t) = (-1)*k1*(k28*x9/k29 - k30*x8/k31)/(1 + x9/k29 + x8/k31)/k1,
  diff(x10, t) = (1*k1*(k32*x8/k33 - k34*x10/k35)/(1 + x8/k33 + x10/k35) + (-1)*k1*(k36*x10/k37 - k38*x11/k39)/(1 + x10/k37 + x11/k39))/k1,
  diff(x11, t) = (1*k1*(k36*x10/k37 - k38*x11/k39)/(1 + x10/k37 + x11/k39) + (-1)*k1*(k40*x11/k41 - k42*k69/k43)/(1 + x11/k41 + k69/k43) + 1*k1*(k54*x12/k55*k68/k56 - k57*x11/k58*k70/k59)/((1 + x12/k55 + x11/k58)*(1 + k68/k56 + k70/k59)))/k1,
  diff(x12, t) = (1*k1*(k44*x5/k45 - k46*x8/k47*x12/k48)/(1 + x5/k45 + x8/k47 + x12/k48 + x5/k45*x8/k47 + x8/k47*x12/k48) + 1*k1*(k49*x5/k50 - k51*x8/k52*x12/k53)/(1 + x5/k50 + x8/k52 + x12/k53 + x5/k50*x8/k52 + x8/k52*x12/k53) + (-1)*k1*(k54*x12/k55*k68/k56 - k57*x11/k58*k70/k59)/((1 + x12/k55 + x11/k58)*(1 + k68/k56 + k70/k59)))/k1,
  diff(x13, t) = 0 }