{ diff(x1, t) = 0,
  diff(x2, t) = 0,
  diff(x3, t) = 0,
  diff(x4, t) = (1*k1*(k2*k72/k3*k73/k4 - k5*k74/k6*x4/k7)/((1 + k72/k3 + k74/k6)*(1 + k73/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*(k48*x5/k49 - k50*x8/k51*x12/k52)/(1 + x5/k49 + x8/k51 + x12/k52 + x5/k49*x8/k51 + x8/k51*x12/k52) + (-1)*k1*(k53*x5/k54 - k55*x8/k56*x12/k57)/(1 + x5/k54 + x8/k56 + x12/k57 + x5/k54*x8/k56 + x8/k56*x12/k57))/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*x9/k23)/(1 + x6/k21 + x9/k23) + (-1)*k1*(k24*x6/k25 - k26*x7/k27)/(1 + x6/k25 + x7/k27) + (-1)*k1*341/10000*((k64*x5/k65 - k66*x6/k67)/(1 + x5/k65 + x6/k67) + (k68*x5/k69 - k70*x6/k71)/(1 + x5/k69 + x6/k71)))/k1,
  diff(x7, t) = (1*k1*(k24*x6/k25 - k26*x7/k27)/(1 + x6/k25 + x7/k27) + (-1)*k1*(k28*x7/k29 - k30*x8/k31)/(1 + x7/k29 + x8/k31))/k1,
  diff(x8, t) = (1*k1*(k28*x7/k29 - k30*x8/k31)/(1 + x7/k29 + x8/k31) + 1*k1*(k32*x9/k33 - k34*x8/k35)/(1 + x9/k33 + x8/k35) + (-1)*k1*(k36*x8/k37 - k38*x10/k39)/(1 + x8/k37 + x10/k39) + 1*k1*(k48*x5/k49 - k50*x8/k51*x12/k52)/(1 + x5/k49 + x8/k51 + x12/k52 + x5/k49*x8/k51 + x8/k51*x12/k52) + 1*k1*(k53*x5/k54 - k55*x8/k56*x12/k57)/(1 + x5/k54 + x8/k56 + x12/k57 + x5/k54*x8/k56 + x8/k56*x12/k57))/k1,
  diff(x9, t) = (1*k1*(k20*x6/k21 - k22*x9/k23)/(1 + x6/k21 + x9/k23) + (-1)*k1*(k32*x9/k33 - k34*x8/k35)/(1 + x9/k33 + x8/k35))/k1,
  diff(x10, t) = (1*k1*(k36*x8/k37 - k38*x10/k39)/(1 + x8/k37 + x10/k39) + (-1)*k1*(k40*x10/k41 - k42*x11/k43)/(1 + x10/k41 + x11/k43))/k1,
  diff(x11, t) = (1*k1*(k40*x10/k41 - k42*x11/k43)/(1 + x10/k41 + x11/k43) + (-1)*k1*(k44*x11/k45 - k46*k73/k47)/(1 + x11/k45 + k73/k47) + 1*k1*(k58*x12/k59*k72/k60 - k61*x11/k62*k74/k63)/((1 + x12/k59 + x11/k62)*(1 + k72/k60 + k74/k63)))/k1,
  diff(x12, t) = (1*k1*(k48*x5/k49 - k50*x8/k51*x12/k52)/(1 + x5/k49 + x8/k51 + x12/k52 + x5/k49*x8/k51 + x8/k51*x12/k52) + 1*k1*(k53*x5/k54 - k55*x8/k56*x12/k57)/(1 + x5/k54 + x8/k56 + x12/k57 + x5/k54*x8/k56 + x8/k56*x12/k57) + (-1)*k1*(k58*x12/k59*k72/k60 - k61*x11/k62*k74/k63)/((1 + x12/k59 + x11/k62)*(1 + k72/k60 + k74/k63)))/k1,
  diff(x13, t) = 0 }