10  LET E = 42
 20  LET T = 2017
 30  GOSUB 500" MODULAR INVERSE
 40  PRINT M;
 50  END

 REM MODULAR INVERSE
 500  LET M = 0
 510  IF E >  = T THEN  RETURN
 520  LET C = 1
 530  FOR B = E TO 1 STEP 0
 540      LET S =  INT ((T - B) / E) + 1
 550      LET B = B + S * E
 560      LET C = C + S
 570      LET B = B - T
 580  NEXT B
 590  LET M = C
 610  RETURN