data segment
  letter db   0
  digit   db   0
  other db   0
data ends

code segment
  assume cs:code,ds:data
start:
  mov ax,data
  mov ds,ax
L1:
  mov ah,1
  int 21h
  cmp al,0Ah   ;忘了是不是0Ah了
  jz exit
  cmp al,30h
  jl L2
  cmp al,39h
  jg L2
  mov ah,digit
  inc ah
  mov digit,ah
  jmp L1

L2:
  cmp al
  cmp al,41h
  jl L3
  cmp al,5ah
  jg L3
  jmp L4
L3:
  cmp al,61h
  jl L5
  cmp ah,7ah
  jg L5
L4:
  mov ah,letter
  inc ah
  mov letter,ah
  jmp L5

L5:
  mov ah,other
  inc ah
  mov other,ah
exit:
  mov ah,4ch
  int 21h
code ends
  end start