ActiveCell.FormulaR1C1 = _
"=IF(ISNA(IF(COUNTIF('Datas CdS'!R2C1:R5000C1,R2C[2])=0,"""",INDEX('Datas CdS'!R1,MATCH(R[2]C2,OFFSET('Datas CdS'!R1C1,MATCH(R2C[2],'Datas CdS'!R2C1:R5000C1),,,256),0)))),"""",IF(COUNTIF('Datas CdS'!R2C1:R5000C1,R2C[2])=0,"""",INDEX('Datas CdS'!R1,MATCH(R[2]C2,OFFSET('Datas CdS'!R1C1,MATCH(R2C[2],'Datas CdS'!R2C1:R5000C1),,,256),0))))"