100 LET A=3 110 LET B=4 120 INPUT N 130 FOR I=1 TO N 140 LET C=(A+B)/2 150 LET D=C*C-2*C-4 160 IF D<0 THEN LET A=C 170 IF D>=0 THEN LET B=C 180 NEXT I 190 PRINT A 200 PRINT B 210 END