Buggy python submission (verdict: Runtime Error):

t=1
# t=int(input())
for _ in range(t):
    from bisect import bisect_left
    n,k=map(int,input().split())
    a=sorted(list(map(int,input().split())))
    m=bisect_left(a,0)
    MOD=10**9+7
    ans=1
    if m==0 or (m==n and k%2==1):
        for i in a[-k:]:
            ans=(ans*i)%MOD
    elif m==n and k%2==0:
        for i in a[:k]:
            ans=(ans*i)%MOD
    else:
        ans=1
        l,r=0,-1
        lm=a[0]*a[1]
        rm=a[-1]*a[-2]
        for i in range(k//2):
            if lm>=rm:
                ans*=lm%MOD
                l+=2
                if l<=n-2:
                    lm=a[l]*a[l+1]
            else:
                ans*=rm%MOD
                r-=2
                if 1<=n+r:
                    rm=a[r]*a[r-1]
            ans%=MOD
        if k%2==1:
            ans*=a[r]
            ans%=MOD
    print(ans)

Fixed submission:
import sys
from functools import lru_cache, cmp_to_key
from heapq import merge, heapify, heappop, heappush
from math import *
from collections import defaultdict as dd, deque, Counter as C
from itertools import combinations as comb, permutations as perm
from bisect import bisect_left as bl, bisect_right as br, bisect
from time import perf_counter
from fractions import Fraction
# import numpy as np
sys.setrecursionlimit(int(pow(10,6)))
# sys.stdin = open("input.txt", "r")
# sys.stdout = open("out.txt", "w")
mod = int(pow(10, 9) + 7)
mod2 = 998244353
def data(): return sys.stdin.readline().strip()
def out(*var, end="\n"): sys.stdout.write(' '.join(map(str, var))+end)
def L(): return list(sp())
def sl(): return list(ssp())
def sp(): return map(int, data().split())
def ssp(): return map(str, data().split())
def l1d(n, val=0): return [val for i in range(n)]
def l2d(n, m, val=0): return [l1d(n, val) for j in range(m)]

# @lru_cache(None)

t=1
# t=int(input())
for _ in range(t):
    n=L()[0]
    if n%1000==0:
        print(0)
        exit()

    print(1000-n%1000)

Buggy python submission (verdict: Runtime Error):
import sys
from functools import lru_cache, cmp_to_key
from heapq import merge, heapify, heappop, heappush
from math import *
from collections import defaultdict as dd, deque, Counter as C
from itertools import combinations as comb, permutations as perm
from bisect import bisect_left as bl, bisect_right as br, bisect
from time import perf_counter
from fractions import Fraction
# import numpy as np
sys.setrecursionlimit(int(pow(10,6)))
# sys.stdin = open("input.txt", "r")
# sys.stdout = open("out.txt", "w")
mod = int(pow(10, 9) + 7)
mod2 = 998244353
def data(): return sys.stdin.readline().strip()
def out(*var, end="\n"): sys.stdout.write(' '.join(map(str, var))+end)
def L(): return list(sp())
def sl(): return list(ssp())
def sp(): return map(int, data().split())
def ssp(): return map(str, data().split())
def l1d(n, val=0): return [val for i in range(n)]
def l2d(n, m, val=0): return [l1d(n, val) for j in range(m)]

# @lru_cache(None)

t=1
# t=int(input())
for _ in range(t):
    n=L()[0]
    print(1000-N%1000)

Fixed submission:
import sys
from functools import lru_cache, cmp_to_key
from heapq import merge, heapify, heappop, heappush
from math import *
from collections import defaultdict as dd, deque, Counter as C
from itertools import combinations as comb, permutations as perm
from bisect import bisect_left as bl, bisect_right as br, bisect
from time import perf_counter
from fractions import Fraction
# import numpy as np
sys.setrecursionlimit(int(pow(10,6)))
# sys.stdin = open("input.txt", "r")
# sys.stdout = open("out.txt", "w")
mod = int(pow(10, 9) + 7)
mod2 = 998244353
def data(): return sys.stdin.readline().strip()
def out(*var, end="\n"): sys.stdout.write(' '.join(map(str, var))+end)
def L(): return list(sp())
def sl(): return list(ssp())
def sp(): return map(int, data().split())
def ssp(): return map(str, data().split())
def l1d(n, val=0): return [val for i in range(n)]
def l2d(n, m, val=0): return [l1d(n, val) for j in range(m)]

# @lru_cache(None)

t=1
# t=int(input())
for _ in range(t):
    n=L()[0]
    if n%1000==0:
        print(0)
        exit()

    print(1000-n%1000)