Сравнить среднее значение пары чисел с txt с числами из этого же текстовика

f = open('<путь к файлу>')
a = [int(i) for i in f]
count = 0
maximum = 0
for i in range(len(a)):
    if a[i] % 2 != 0 and a[i + 1] % 2 != 0:
        s = a[i] + a[i + 1]
        sred = s // 2
        for j in range(len(a)):
            if sred == a[j]:
                count += 1
print(count)

count = 0
for i in range(len(a)):
    if a[i] % 2:
        count += sum([(a[i] + a[j]) // 2 in a for j in range(i+1, len(a)) if a[j] %2 ])
print(count)

if a[i] % 2 !=0:

if a[i] % 2 ==1:

count = 0
a.sort()
for i in range(len(a)):
    if a[i] % 2:
        for j in range(i+1, len(a)):
            if a[j] % 2:
                sred = (a[i] + a[j]) // 2
                for k in range(i,j):
                    if sred == a[k]:
                        count += 1
print(count)

print(sum([sum([(u+v)//2 in a for j, v in enumerate(a[i+1:]) if v%2]) for i, u in enumerate(a[:-1]) if u%2]))

from itertools import combinations as cmb
 
with open ('26.txt') as f:
    _, *nums = map(int, f.read().splitlines())
nums = set(nums)
odd = [e for e in nums if e%2]
 
res = [sum(elem)//2 
     for elem in cmb(odd, 2) 
     if sum(elem)//2 in nums]
print(len(res), max(res))