Buggy python submission (verdict: Runtime Error):
import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians, gcd
# from fractions import gcd
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from functools import reduce
from bisect import bisect_left, insort_left
from heapq import heapify, heappush, heappop

INPUT = lambda: sys.stdin.readline().rstrip()
INT = lambda: int(INPUT())
MAP = lambda: map(int, INPUT().split())
S_MAP = lambda: map(str, INPUT().split())
LIST = lambda: list(map(int, INPUT().split()))
S_LIST = lambda: list(map(str, INPUT().split()))
ZIP = lambda: zip(*(MAP() for _ in range(n)))

sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7


def main():
    N, K = MAP()

    r = N%K
    if r == 0:
        print(0)
    else:
        if 2*r > K:
            print(abs(r - K))
        else:
            print(r)


if __name__ == '__main__':
    main()


Fixed submission:
import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
# from fractions import gcd
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from functools import reduce
from bisect import bisect_left, insort_left
from heapq import heapify, heappush, heappop

INPUT = lambda: sys.stdin.readline().rstrip()
INT = lambda: int(INPUT())
MAP = lambda: map(int, INPUT().split())
S_MAP = lambda: map(str, INPUT().split())
LIST = lambda: list(map(int, INPUT().split()))
S_LIST = lambda: list(map(str, INPUT().split()))
ZIP = lambda: zip(*(MAP() for _ in range(n)))

sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7


def main():
    N, K = MAP()

    r = N%K
    if r == 0:
        print(0)
    else:
        if 2*r > K:
            print(abs(r - K))
        else:
            print(r)


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians, gcd
# from fractions import gcd
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from functools import reduce
from bisect import bisect_left, insort_left
from heapq import heapify, heappush, heappop

INPUT = lambda: sys.stdin.readline().rstrip()
INT = lambda: int(INPUT())
MAP = lambda: map(int, INPUT().split())
S_MAP = lambda: map(str, INPUT().split())
LIST = lambda: list(map(int, INPUT().split()))
S_LIST = lambda: list(map(str, INPUT().split()))
ZIP = lambda: zip(*(MAP() for _ in range(n)))

sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7


def main():
    N, K = MAP()

    ans = gcd(N, K) 
    print(0 if ans == 1 else ans)


if __name__ == '__main__':
    main()


Fixed submission:
import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
# from fractions import gcd
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from functools import reduce
from bisect import bisect_left, insort_left
from heapq import heapify, heappush, heappop

INPUT = lambda: sys.stdin.readline().rstrip()
INT = lambda: int(INPUT())
MAP = lambda: map(int, INPUT().split())
S_MAP = lambda: map(str, INPUT().split())
LIST = lambda: list(map(int, INPUT().split()))
S_LIST = lambda: list(map(str, INPUT().split()))
ZIP = lambda: zip(*(MAP() for _ in range(n)))

sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7


def main():
    N, K = MAP()

    r = N%K
    if r == 0:
        print(0)
    else:
        if 2*r > K:
            print(abs(r - K))
        else:
            print(r)


if __name__ == '__main__':
    main()