(a/2 + b) / 4 + c - 1

section .data
fmtin: db "%d%d%d", 0
fmtout: db "%d", 0
two: dd 2
one: dd 1

section .bss
a: resd 1
b: resd 1
c: resd 1
x: resd 1

section .text
extern _printf
extern _scanf
global _main

_main:
push c
push b
push a
push fmtin
call _scanf
add esp, 16

mov eax, [a]
div dword [two]
add eax, [b]
div dword [two]
div dword [two]
add eax, [c]
sub eax, [one]
mov [x], eax
push dword [x]
push fmtout
call _printf
add esp, 8
xor eax, eax
ret