=SI(A2&B2=A1&B1;"";SI(NB.SI($A$2:$A$21;A2)=NB.SI($B$2:$B$21;B2);"Bloc "&NB.SI(D$11;"Bloc*")+1;""))
=SI(A2&B2=A1&B1=A3&B3;"Bloc";SI(NB.SI($A$2:$A$21;A2)=NB.SI($B$2:$B$21;B2);"Bloc";""))
=SI(A2&B2=A1&B1=A3&B3;"Bloc";SI(NB.SI($A$2:$A$21;A2)=NB.SI($B$2:$B$21;B2);"Bloc";"-"))
suffit ?=SI(NB.SI($A$2:$A$21;A2)=NB.SI($B$2:$B$21;B2);"Bloc";"")