Buggy python submission (verdict: Runtime Error):
n = int(input())
def f(x):
  for k in range(2, int(sqrt(x)) + 1):
    if x % k != 0:
      continue
      return False
    return True
i = n
while 1:
  if f(i):
    print(i)
    break
  i += 1

Fixed submission:
#!/usr/bin/env python3
from collections import defaultdict,deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys, random, itertools, math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt
def LI(): return list(map(int, input().split()))
def LF(): return list(map(float, input().split()))
def LI_(): return list(map(lambda x: int(x)-1, input().split()))
def II(): return int(input())
def IF(): return float(input())
def LS(): return list(map(list, input().split()))
def S(): return list(input().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def primes(n):
    """ 
    Input n>=6, Returns a list of primes, 2 <= p < n 
    6以上の数であれば p (素数) <= n のlistを返す 
    :param int n:
    :rytpe list:
    """
    n, correction = n-n%6+6, 2-(n%6>1)
    sieve = [True] * (n//3)
    for i in range(1,int(n**0.5)//3+1):
        if sieve[i]:
            k=3*i+1|1
            sieve[      k*k//3      ::2*k] = [False] * ((n//6-k*k//6-1)//k+1)
            sieve[k*(k-2*(i&1)+4)//3::2*k] = [False] * ((n//6-k*(k-2*(i&1)+4)//6-1)//k+1)
    return [2,3] + [3*i+1|1 for i in range(1,n//3-correction) if sieve[i]]

#solve
def solve():
    x = II()
    p = primes(10 ** 6)
    print(p[bisect_left(p, x)])
    return


#main
if __name__ == '__main__':
    solve()

Buggy python submission (verdict: Runtime Error):
n = int(input())
def f(x):
  for k in range(2, int(sqrt(x)) + 1):
    if x % k != 0:
      continue
      return False
    return True
  i = n
while 1:
  if f(i):
    print(i)
    break
  i += 1

Fixed submission:
#!/usr/bin/env python3
from collections import defaultdict,deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys, random, itertools, math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt
def LI(): return list(map(int, input().split()))
def LF(): return list(map(float, input().split()))
def LI_(): return list(map(lambda x: int(x)-1, input().split()))
def II(): return int(input())
def IF(): return float(input())
def LS(): return list(map(list, input().split()))
def S(): return list(input().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def primes(n):
    """ 
    Input n>=6, Returns a list of primes, 2 <= p < n 
    6以上の数であれば p (素数) <= n のlistを返す 
    :param int n:
    :rytpe list:
    """
    n, correction = n-n%6+6, 2-(n%6>1)
    sieve = [True] * (n//3)
    for i in range(1,int(n**0.5)//3+1):
        if sieve[i]:
            k=3*i+1|1
            sieve[      k*k//3      ::2*k] = [False] * ((n//6-k*k//6-1)//k+1)
            sieve[k*(k-2*(i&1)+4)//3::2*k] = [False] * ((n//6-k*(k-2*(i&1)+4)//6-1)//k+1)
    return [2,3] + [3*i+1|1 for i in range(1,n//3-correction) if sieve[i]]

#solve
def solve():
    x = II()
    p = primes(10 ** 6)
    print(p[bisect_left(p, x)])
    return


#main
if __name__ == '__main__':
    solve()

Buggy python submission (verdict: Runtime Error):
n = int(input())
def f(x):
    for k in range(2, int(sqrt(x)) + 1):
        if x % k == 0:
            continue
        return False
    return True
i = n
while 1:
    if f(i):
        print(i)
        break
    i += 1

Fixed submission:
#!/usr/bin/env python3
from collections import defaultdict,deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys, random, itertools, math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt
def LI(): return list(map(int, input().split()))
def LF(): return list(map(float, input().split()))
def LI_(): return list(map(lambda x: int(x)-1, input().split()))
def II(): return int(input())
def IF(): return float(input())
def LS(): return list(map(list, input().split()))
def S(): return list(input().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def primes(n):
    """ 
    Input n>=6, Returns a list of primes, 2 <= p < n 
    6以上の数であれば p (素数) <= n のlistを返す 
    :param int n:
    :rytpe list:
    """
    n, correction = n-n%6+6, 2-(n%6>1)
    sieve = [True] * (n//3)
    for i in range(1,int(n**0.5)//3+1):
        if sieve[i]:
            k=3*i+1|1
            sieve[      k*k//3      ::2*k] = [False] * ((n//6-k*k//6-1)//k+1)
            sieve[k*(k-2*(i&1)+4)//3::2*k] = [False] * ((n//6-k*(k-2*(i&1)+4)//6-1)//k+1)
    return [2,3] + [3*i+1|1 for i in range(1,n//3-correction) if sieve[i]]

#solve
def solve():
    x = II()
    p = primes(10 ** 6)
    print(p[bisect_left(p, x)])
    return


#main
if __name__ == '__main__':
    solve()