Buggy python submission (verdict: Runtime Error):
def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort()
    return divisors

def make_codivisors(n):
    divisors = []
    n0divisors = make_divisors(n[0])
    n0len = len(n0divisors)
    for i in n0divisors:
        for j in range(1, len(n)):
            if n[j] % i != 0:
                break
            if j == len(n)-1:
                divisors.append(i)
            
    # divisors.sort()
    return max(divisors)


n, x = list(map(int, input().split()))
a = list(map(int, input().split()))
a.append(x)
a.sort()
b = [a[i]-a[i-1] for i in range(1, n+1)]

#print(b)
#print(a)

print(make_codivisors(b))

Fixed submission:
def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort()
    return divisors

def make_codivisors(n):
    divisors = []
    n0divisors = make_divisors(n[0])
    n0len = len(n0divisors)
    for i in n0divisors:
        for j in range(1, len(n)):
            if n[j] % i != 0:
                break
            if j == len(n)-1:
                divisors.append(i)
            
    # divisors.sort()
    return max(divisors)


n, x = list(map(int, input().split()))
a = list(map(int, input().split()))
a.append(x)
a.sort()
b = [a[i]-a[i-1] for i in range(1, n+1)]

#print(b)
#print(a)
if len(b) >= 2:
  print(make_codivisors(b))
else:
  print(b[0])

Buggy python submission (verdict: Runtime Error):
def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort()
    return divisors

def make_codivisors(n):
    divisors = []
    n0divisors = make_divisors(n[0])
    n0len = len(n0divisors)
    for i in n0divisors:
        for j in range(1, len(n)):
            if n[j] % i != 0:
                break
            if j == len(n)-1:
                divisors.append(i)
            
    # divisors.sort()
    return max(divisors)


n, x = list(map(int, input().split()))
a = list(map(int, input().split()))
a.append(x)
a.sort()
b = [a[i]-a[i-1] for i in range(1, n+1)]

print(b)
print(a)

print(make_codivisors(b))

Fixed submission:
def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort()
    return divisors

def make_codivisors(n):
    divisors = []
    n0divisors = make_divisors(n[0])
    n0len = len(n0divisors)
    for i in n0divisors:
        for j in range(1, len(n)):
            if n[j] % i != 0:
                break
            if j == len(n)-1:
                divisors.append(i)
            
    # divisors.sort()
    return max(divisors)


n, x = list(map(int, input().split()))
a = list(map(int, input().split()))
a.append(x)
a.sort()
b = [a[i]-a[i-1] for i in range(1, n+1)]

#print(b)
#print(a)
if len(b) >= 2:
  print(make_codivisors(b))
else:
  print(b[0])