Buggy python submission (verdict: Runtime Error):
def resolve():
    '''
    code here
    '''
    S = input()
    is_flag = True
    while is_flag:
        # print(S, len(S))
        if len(S)>=5:
            temp = S[:5]
            # print(temp)
            if temp == 'dream':
                S = S[5:]
                if S[:5] == 'erase':
                    pass
                elif S[:2] == 'er':
                    S = S[2:]
                
            elif temp == 'erase':
                S = S[5:]
                if S[0] == 'r':
                    S = S[1:]
            else:
                print('NO')
                is_flag = False
        elif len(S) == 0:
            print('YES')
            is_flag = False
        else:
            print('NO')
            is_flag = False


if __name__ == "__main__":
    resolve()


Fixed submission:
def resolve():
    '''
    code here
    '''
    S = input()
    is_flag = True
    while is_flag:
        # print(S, len(S))
        if len(S)>=5:
            temp = S[:5]
            # print(temp)
            if temp == 'dream':
                S = S[5:]
                if len(S) != 0:
                    if S[:5] == 'erase':
                        pass
                    elif S[:2] == 'er':
                        S = S[2:]
                
            elif temp == 'erase':
                S = S[5:]
                if len(S) != 0:
                    if S[0] == 'r':
                        S = S[1:]

            else:
                print('NO')
                is_flag = False
        elif len(S) == 0:
            print('YES')
            is_flag = False
        else:
            print('NO')
            is_flag = False


if __name__ == "__main__":
    resolve()

Buggy python submission (verdict: Runtime Error):
def resolve():
    '''
    code here
    '''
    S = input()
    is_flag = True
    while is_flag:
        # print(S, len(S))
        if len(S)>=5:
            temp = S[:5]
            # print(temp)
            if temp == 'dream':
                S = S[5:]
                if S[:5] == 'erase':
                    pass
                elif S[:2] == 'er':
                    S = S[2:]
                
            elif temp == 'erase':
                S = S[5:]
                if S[0] == 'r':
                    S = S[1:]
            else:
                print('NO')
                is_flag = False
        elif len(S) == 0:
            print('YES')
            is_flag = False
        else:
            print('NO')
            is_flag = False


if __name__ == "__main__":
    resolve()


Fixed submission:
def resolve():
    '''
    code here
    '''
    S = input()
    is_flag = True
    while is_flag:
        # print(S, len(S))
        if len(S)>=5:
            temp = S[:5]
            # print(temp)
            if temp == 'dream':
                S = S[5:]
                if len(S) != 0:
                    if S[:5] == 'erase':
                        pass
                    elif S[:2] == 'er':
                        S = S[2:]
                
            elif temp == 'erase':
                S = S[5:]
                if len(S) != 0:
                    if S[0] == 'r':
                        S = S[1:]

            else:
                print('NO')
                is_flag = False
        elif len(S) == 0:
            print('YES')
            is_flag = False
        else:
            print('NO')
            is_flag = False


if __name__ == "__main__":
    resolve()