The answer is 91
( y0 X: g2 u% y' M# \& I; Ktvb now,tvbnow,bttvb1 row 3x4+1x3=155.39.217.773 ^; U' R, ~5 {6 ?7 ~
2 row 4x5+2x4=28
. x$ `- _) c+ ]7 k/ l. b公仔箱論壇3 row 5x6+3x5=455.39.217.77( l+ A" r# a# b1 x9 z3 i" a3 s
4 row 6x7+4x6=66
% t6 q$ u; j9 g: a3 ~tvb now,tvbnow,bttvb5 row 7x8+5x7=91  |