3dmax fbx vertex count and unity vertex count

Unity Engine
1

hi,i spectify 28 pic faces with 28*3=84 vertexes to flat the mesh.how to match the vertex count and vertex normal from fbx to unity?in max, has 84 vertexes in 0:vc channel,export to
unity got 42 vertexes.how make 82 vertexes as in max?

3100665--234078--max.png
3100665--234078--max.png792×218 4.92 KB
3100665--234077--u.jpg
3100665--234077--u.jpg1608×318 36.2 KB
3100665--234081--max2.png
3100665--234081--max2.png926×719 23.2 KB

2

anybody?