diff --git a/src/aig/gia/giaSweeper.c b/src/aig/gia/giaSweeper.c
index 735abf30a..b4a53f44a 100644
--- a/src/aig/gia/giaSweeper.c
+++ b/src/aig/gia/giaSweeper.c
@@ -758,7 +758,10 @@ static Vec_Int_t * Gia_ManGetCex( Gia_Man_t * pGia, Vec_Int_t * vId2Lit, sat_sol
     Gia_ManForEachPi( pGia, pObj, i )
     {
         if ( Gia_ObjId(pGia, pObj) >= Vec_IntSize(vId2Lit) )
+        {
+            Vec_IntPush( vCex, 2 );
             continue;
+        }
         LitSat = Vec_IntEntry( vId2Lit, Gia_ObjId(pGia, pObj) );
         if ( LitSat == 0 )
         {