=SI(ESTERREUR(INDIRECT("S"&STXT(STXT(CELLULE("filename";$A$1);TROUVE("]";CELLULE("filename";$A$1))+1;255);2;10)-1&"!M"&LIGNES($1:16)));0;INDIRECT("S"&STXT(STXT(CELLULE("filename";$A$1);TROUVE("]";CELLULE("filename";$A$1))+1;255);2;10)-1&"!M"&LIGNES($1:16)))