The answer is 91
2 x, Y" M- C- c* |. ~: B$ i公仔箱論壇1 row 3x4+1x3=15
2 _$ ^% p# _1 l6 \9 Qtvb now,tvbnow,bttvb2 row 4x5+2x4=28
; H! `4 k( u3 z, b# O& I/ R& m5.39.217.773 row 5x6+3x5=45
+ w& `3 ^6 H" P& D( u5 c+ rtvb now,tvbnow,bttvb4 row 6x7+4x6=661 ]$ H) X2 W) n
5 row 7x8+5x7=91  |