diff --git a/src/cipsi/pt2_stoch_routines.irp.f b/src/cipsi/pt2_stoch_routines.irp.f
index 069bcfd9..e9a1f724 100644
--- a/src/cipsi/pt2_stoch_routines.irp.f
+++ b/src/cipsi/pt2_stoch_routines.irp.f
@@ -19,7 +19,7 @@ END_PROVIDER
   do i=1,pt2_n_0(1+pt2_N_teeth/4)
     pt2_F(i) = pt2_n_tasks_max
   enddo
-  do i=pt2_n_0(pt2_N_teeth-pt2_N_teeth/4), N_det_generators
+  do i=1+pt2_n_0(pt2_N_teeth-pt2_N_teeth/4), N_det_generators
     pt2_F(i) = 1
   enddo