Buggy python submission (verdict: Runtime Error):
S = str(input())
stack = []
N = len(S)
for i, s in enumerate(S):
  if i == 0:
    stack.append(s)
    else:
      if len(stack) == 0:
        stack.append(s)
        else:
          if s != stack[-1]:
            tmp = stack.pop()
            else:
              stack.append(s)
print(N - len(stack))


Fixed submission:
#!/usr/bin/env python3
import sys


def solve(S: str):
    stack = []
    N = len(S)
    for i, s in enumerate(S):
        if i == 0:
            stack.append(s)
        else:
            if len(stack) == 0:
                stack.append(s)
            else:
                if s != stack[-1]:
                    tmp = stack.pop()
                else:
                    stack.append(s)
    print(N - len(stack))

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
S = str(input())
ans = 0
N = len(S)
while True:
  S = S.replace('10', '').replace('01', '')
  if S.count('10') == 0 and S.count('01') == 0:
    break
ans = N - len(S)
print(ans)

Fixed submission:
#!/usr/bin/env python3
import sys


def solve(S: str):
    stack = []
    N = len(S)
    for i, s in enumerate(S):
        if i == 0:
            stack.append(s)
        else:
            if len(stack) == 0:
                stack.append(s)
            else:
                if s != stack[-1]:
                    tmp = stack.pop()
                else:
                    stack.append(s)
    print(N - len(stack))

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin/env python3
import sys


def solve(S: str):
    ans = 0
    N = len(S)
    while True:
        S = S.replace('10', '').replace('01', '')
        if S.count('10') == 0 and S.count('01') == 0:
            break
    ans = N - len(S)
    print(ans)

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin/env python3
import sys


def solve(S: str):
    stack = []
    N = len(S)
    for i, s in enumerate(S):
        if i == 0:
            stack.append(s)
        else:
            if len(stack) == 0:
                stack.append(s)
            else:
                if s != stack[-1]:
                    tmp = stack.pop()
                else:
                    stack.append(s)
    print(N - len(stack))

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin/env python3
import sys


def solve(S: str):
    ans = 0
    if S == '0':
        print(ans)
        return
    N = len(S)
    while True:
        S = S.replace('10', '').replace('01', '')
        if S.count('10') == 0 and S.count('01') == 0:
            break
    ans = N - len(S)
    print(ans)

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin/env python3
import sys


def solve(S: str):
    stack = []
    N = len(S)
    for i, s in enumerate(S):
        if i == 0:
            stack.append(s)
        else:
            if len(stack) == 0:
                stack.append(s)
            else:
                if s != stack[-1]:
                    tmp = stack.pop()
                else:
                    stack.append(s)
    print(N - len(stack))

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin/env python3
import sys


def solve(S: str):
    ans = 0
    if S == '0':
        print(ans)
        return
    N = len(S)
    for i in range(min(S.count('0'), S.count('1'))):
        if len(S) > 0:
            S = S.replace('10', '')
            S = S.replace('01', '')
        else:
            break
        if S.count('10') == 0 and S.count('01') == 0:
            break
    ans = N - len(S)
    print(ans)

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin/env python3
import sys


def solve(S: str):
    stack = []
    N = len(S)
    for i, s in enumerate(S):
        if i == 0:
            stack.append(s)
        else:
            if len(stack) == 0:
                stack.append(s)
            else:
                if s != stack[-1]:
                    tmp = stack.pop()
                else:
                    stack.append(s)
    print(N - len(stack))

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin/env python3
import sys


def solve(S: str):
    ans = 0
    if S == '0':
        print(ans)
        return
    N = len(S)
    for i in range(min(S.count('0'), S.count('1'))):
        if len(S) > 0:
            S = S.replace('10', '')
            S = S.replace('01', '')
        else:
            break
    ans = N - len(S)
    print(ans)
# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    S = str(next(tokens))  # type: str
    solve(S)

if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin/env python3
import sys


def solve(S: str):
    stack = []
    N = len(S)
    for i, s in enumerate(S):
        if i == 0:
            stack.append(s)
        else:
            if len(stack) == 0:
                stack.append(s)
            else:
                if s != stack[-1]:
                    tmp = stack.pop()
                else:
                    stack.append(s)
    print(N - len(stack))

# Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools  (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    S = str(input())
    solve(S)

if __name__ == '__main__':
    main()