=TEXTE(DATE(1900;4;26-MOD(11*MOD(A2;19)+ENT(ENT(A2/100)/4)+ENT(8*(ENT(A2/100)+11)/25)-ENT(A2/100)+41;30)-ENT((552-19*MOD(11*MOD(A2;19)+ENT(ENT(A2/100)/4)+ENT(8*(ENT(A2/100)+11)/25)-ENT(A2/100)+41;30)+MOD(A2;19))/544)-MOD(MOD(50-MOD(11*MOD(A2;19)+ENT(ENT(A2/100)/4)+ENT(8*(ENT(A2/100)+11)/25)-ENT(A2/100)+41;30)-ENT((552-19*MOD(11*MOD(A2;19)+ENT(ENT(A2/100)/4)+ENT(8*(ENT(A2/100)+11)/25)-ENT(A2/100)+41;30)+MOD(A2;19))/544);7)+MOD(MOD(9-2*MOD(ENT(A2/100);4);7)+MOD(A2;100)+ENT(MOD(A2;100)/4);7);7));"jj-mm-")&A2