The answer is 91 
0 f6 E! U6 }7 Z; ], a% f- F5.39.217.77:88981 row 3x4+1x3=15 
8 {0 K3 `5 M- s& f3 u3 n2 row 4x5+2x4=28 
  \  _, [! ?3 l( X. ttvb now,tvbnow,bttvb3 row 5x6+3x5=45 
9 p8 `( a8 |9 V5 L. e3 C公仔箱論壇4 row 6x7+4x6=66 
8 l0 w+ x+ y0 A# q% t+ [0 t" R5 row 7x8+5x7=91   |