Buggy python submission (verdict: Time Limit Exceeded):
def reflesh_string(current_answer):
    index = min(K, len(current_answer))
    return current_answer[:index]

def update_string(string_answer):
    string_answer = string_answer.replace("1", "1")
    string_answer = string_answer.replace("2", "22")
    string_answer = string_answer.replace("3", "333")
    string_answer = string_answer.replace("4", "4444")
    string_answer = string_answer.replace("5", "55555")
    string_answer = string_answer.replace("6", "666666")
    string_answer = string_answer.replace("7", "7777777")
    string_answer = string_answer.replace("8", "88888888")
    string_answer = string_answer.replace("9", "999999999")
    return string_answer
  
def check_skip(current_answer):
    counter = [0 for i in range(10)]
    for k in range(min(K, len(current_answer))):
        counter[int(current_answer[k])] = 1
    if(sum(counter) == 1):
        return True
    
    if(sum(counter) == 2 and current_answer[min(K, len(current_answer)) - 1] != "1"):
        return True
    
    return False
    
S = input().strip()
K = int(input().strip())
for c in range(5 * 10**15):
    S = update_string(S)
    S = reflesh_string(S)
    if(check_skip(S)):
        break
print(S[min(K, len(S)) - 1])

Fixed submission:
S = input().strip()
K = int(input().strip())

ans = 1
for i in range(min(K, len(S))):
    if(S[i] != "1"):
        ans = S[i]
        break
        
print(ans)

Buggy python submission (verdict: Runtime Error):
def reflesh_string(current_answer):
    index = min(K, len(current_answer))
    return current_answer[:index]

def update_string(string_answer):
    string_answer = string_answer.replace("1", "1")
    string_answer = string_answer.replace("2", "22")
    string_answer = string_answer.replace("3", "333")
    string_answer = string_answer.replace("4", "4444")
    string_answer = string_answer.replace("5", "55555")
    string_answer = string_answer.replace("6", "666666")
    string_answer = string_answer.replace("7", "7777777")
    string_answer = string_answer.replace("8", "88888888")
    string_answer = string_answer.replace("9", "999999999")
    return string_answer
  
def check_skip(current_answer):
    counter = [0 for i in range(9)]
    for k in range(min(K, len(current_answer))):
        counter[int(current_answer[k])] = 1
    if(sum(counter) == 1):
        return True
    
    if(sum(counter) == 2 and current_answer[min(K, len(current_answer)) - 1] != "1"):
        return True
    
    return False
    
S = input().strip()
K = int(input().strip())
for c in range(5 * 10**15):
    S = update_string(S)
    S = reflesh_string(S)
    if(check_skip(S)):
        break
print(S[min(K, len(S)) - 1])

Fixed submission:
S = input().strip()
K = int(input().strip())

ans = 1
for i in range(min(K, len(S))):
    if(S[i] != "1"):
        ans = S[i]
        break
        
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
def reflesh_string(current_answer):
    index = min(K, len(current_answer))
    return current_answer[:index]
  
def update_string(string_answer):
    string_answer = string_answer.replace("1", "1")
    string_answer = string_answer.replace("2", "22")
    string_answer = string_answer.replace("3", "333")
    string_answer = string_answer.replace("4", "4444")
    string_answer = string_answer.replace("5", "55555")
    string_answer = string_answer.replace("6", "666666")
    string_answer = string_answer.replace("7", "7777777")
    string_answer = string_answer.replace("8", "88888888")
    string_answer = string_answer.replace("9", "999999999")
    return string_answer
  
def check_skip(current_answer):
    for i in range(2, 10):
        i = str(i)
        if(i in current_answer):
            return False
    return True
  
S = input().strip()
K = int(input().strip())
for c in range(5 * 10**15):
    S = update_string(S)
    S = reflesh_string(S)
    if(check_skip(S)):
        break
print(S[K-1])

Fixed submission:
S = input().strip()
K = int(input().strip())

ans = 1
for i in range(min(K, len(S))):
    if(S[i] != "1"):
        ans = S[i]
        break
        
print(ans)