diff --git a/PhysicsTools/JetMCAlgos/plugins/GenHFHadronMatcher.cc b/PhysicsTools/JetMCAlgos/plugins/GenHFHadronMatcher.cc
index 4cb97a0140f53..5a785eb72b444 100644
--- a/PhysicsTools/JetMCAlgos/plugins/GenHFHadronMatcher.cc
+++ b/PhysicsTools/JetMCAlgos/plugins/GenHFHadronMatcher.cc
@@ -979,7 +979,8 @@ int GenHFHadronMatcher::findInMothers(int idx,
     }
     int pdg_2 = hadMothers[idx2].pdgId();
     // Inverting the flavour if bb oscillation detected
-    if (isHadronPdgId(pdgId, pdg_1) && isHadronPdgId(pdgId, pdg_2) && pdg_1 * pdg_2 < 0) {
+    if (isHadronPdgId(pdgId, pdg_1) && isHadronPdgId(pdgId, pdg_2) &&
+        ((pdg_1 < 0 && pdg_2 > 0) || (pdg_1 > 0 && pdg_2 < 0))) {
       pdgId *= -1;
       if (verbose)
         printf("######### Inverting flavour of the hadron\n");