diff --git a/docs/tutorials/05-entanglement-forging.ipynb b/docs/tutorials/05-entanglement-forging.ipynb
index c5adf768b..740abb417 100644
--- a/docs/tutorials/05-entanglement-forging.ipynb
+++ b/docs/tutorials/05-entanglement-forging.ipynb
@@ -45,22 +45,19 @@
     "\n",
     "# Define active space\n",
     "active_space = [1, 2, 4, 5, 6]\n",
-    "norb = len(active_space)\n",
-    "n_electrons = int(sum(hartree_fock.mo_occ[active_space]))\n",
-    "n_alpha = (n_electrons + hartree_fock.mol.spin) // 2\n",
-    "n_beta = (n_electrons - hartree_fock.mol.spin) // 2\n",
-    "nelec = (n_alpha, n_beta)\n",
-    "\n",
-    "# Compute FCI energy\n",
-    "cas = pyscf.mcscf.CASCI(hartree_fock, ncas=len(active_space), nelecas=nelec)\n",
-    "mo = cas.sort_mo(active_space, base=0)\n",
-    "energy_fci = cas.kernel(mo)[0]\n",
     "\n",
     "# Get molecular data and molecular Hamiltonian (one- and two-body tensors)\n",
     "mol_data = ffsim.MolecularData.from_hartree_fock(\n",
     "    hartree_fock, active_space=active_space\n",
     ")\n",
-    "mol_hamiltonian = mol_data.hamiltonian"
+    "norb = mol_data.norb\n",
+    "nelec = mol_data.nelec\n",
+    "mol_hamiltonian = mol_data.hamiltonian\n",
+    "\n",
+    "# Compute FCI energy\n",
+    "cas = pyscf.mcscf.CASCI(hartree_fock, ncas=mol_data.norb, nelecas=mol_data.nelec)\n",
+    "mo = cas.sort_mo(active_space, base=0)\n",
+    "energy_fci = cas.kernel(mo)[0]"
    ]
   },
   {