{ diff(x1, t) = 1*(k7*(k2*x26 + x27 + k3*x28) - x1)/k51,
  diff(x2, t) = 1*(1/k1*(k10*x1 - k17*x2*x3 + k18*x4) + k16*(k20*x6 - k19*x2*x14))/k51,
  diff(x3, t) = 1*1/k1*(k21*x8*x13 - k22*x3 + (k18 + 1)*x4 - k17*x3*x2)/k51,
  diff(x4, t) = 1*1/k1*(k17*x2*x3 - (k18 + 1)*x4)/k51,
  diff(x5, t) = 1*1/k1*(x4 - k14*x5)/k51,
  diff(x6, t) = 1*(k19*x14*x2 - k20*x6)/k51,
  diff(x7, t) = 1*(k23*x14^2 - k24*x7)/k51,
  diff(x8, t) = 1*(k13*(k4 - x8) - 1/k1*k15*(k21*x8*x13 - k22*x3))/k51,
  diff(x9, t) = 1*(k9*(k2*x30 + x31) - x9)/k51,
  diff(x10, t) = 1*1/k1*(k12*x9 - x10)/k51,
  diff(x11, t) = 1*(k8*(k2*x30 + x31) - x11)/k51,
  diff(x12, t) = 1*1/k1*(k11*x11 - x12)/k51,
  diff(x15, t) = 1*(k36*x29 - x15)/k51,
  diff(x16, t) = 1*1/k1*(k38*x15 - x16)/k51,
  diff(x17, t) = 1*1/k1*(k44*x24 - k43*x17*x18)/k51,
  diff(x18, t) = 1*(k40*(k32 - x18) - k42/k1*(k43*x17*x18 - k44*x24))/k51,
  diff(x19, t) = 1*1/k1*(k45*x24*x23 - k46*x25*x19)/k51,
  diff(x20, t) = 1*1/k1*(k47*x24*x22 - k48*x25*x20)/k51,
  diff(x21, t) = 1*(k37*x32 - x21)/k51,
  diff(x22, t) = 1*1/k1*(k39*x21 - x22 + k41*(k48*x25*x20 - k47*x24*x22))/k51 }