Операнды арифметического выражения записаны в системе счисления с основанием 15

ans = []
for x in range(10):
    a = 6 * 15 ** 7 + 7 * 15 ** 6 + 8 * 15 ** 5 + 4 * 15 ** 4 + 5 * 15 ** 3 + x * 15 ** 2 + 6 * 15 + 5
    b = 15 ** 6 + x * 15 ** 5 + 2 * 15 ** 4 + 3 * 15 ** 3 + 4 * 15 ** 2 + 5 * 15 + 6
    if (a + b) % 14 == 0:
        ans.append((a + b) // 14)
print(ans[-1])

def sum_digits(s):
    d = '0123456789ABCDE'
    res = 0
    for i in range(len(s)):
        if s[i] in d:
            res += d.index(s[i])
    return(res)
 
def from15do10(s):
    d = '0123456789ABCDE'
    res = d.index(s[-1])
    for i in range(2, len(s)+1):
        res += d.index(s[-i])*(15**(i-1))
    return res
 
s1, s2 = input().split(' + ')
ds = sum_digits(s1) + sum_digits(s2)
x = (14-ds%14)//2
while x < 7:
    x += 7
d = '0123456789ABCDE'
s1 = s1.replace('x', d[x])
s2 = s2.replace('x', d[x])
a = from15do10(s1)
b = from15do10(s2)
print((a+b)//14)

80788834

ans = []
for x in range(15): 
    a = 6 * 15 ** 7 + 7 * 15 ** 6 + 8 * 15 ** 5 + 4 * 15 ** 4 + 5 * 15 ** 3 + x * 15 ** 2 + 6 * 15 + 5
    b = 1 * 15 ** 6 + x * 15 ** 5 + 2 * 15 ** 4 + 3 * 15 ** 3 + 4 * 15 ** 2 + 5 * 15 + 6  
    if (a + b) % 14 == 0:
        ans.append((a + b) // 14)
print(ans[-1])

BASE = 15
for d in reversed(range(BASE)):
    num = sum(int(s.replace('x', hex(d)[2:]), BASE) for s in ('67845x65', '1x23456'))
    num, rem = divmod(num, BASE-1)
    if not rem:
        print(num)
        break

def convert_from_base(num, base):
    num_str = str(num)
 
    result = 0
    index = len(num_str) - 1
    for digit in num_str:
        result += int(digit) * (base ** index)
        index -= 1
    return result
 
 
for x in range(0, 15)[::-1]:
    num = convert_from_base(int(f"67845{x}65"), 15) + convert_from_base(int(f"1{x}23456"), 15)
    if num % 14 == 0:
        print(num / 14)
        break