def reverse_delete(s,c):
    """Task
    We are given two strings s and c, you have to deleted all the characters in s that are equal to any character in c
    then check if the result string is palindrome.
    A string is called palindrome if it reads the same backward as forward.
    You should return a tuple containing the result string and True/False for the check.
    Example
    For s = "abcde", c = "ae", the result should be ('bcd',False)
    For s = "abcdef", c = "b"  the result should be ('acdef',False)
    For s = "abcdedcba", c = "ab", the result should be ('cdedc',True)
    
    Example solution:
    # line 1
    ret = ''
    # line 2
    for char in s:
        # line 3
        if char in c:
            # line 4
            ret += char
    # line 5
    return (ret,ret[::-1] == ret)
    
    """
    # Please print out which line of the above program contains an error. E.g. if the bug is on line 4 then print 4
    # END OF CONTEXT
    print("3")
    # END OF SOLUTION

def check(candidate):

    import io
    from contextlib import redirect_stdout

    f = io.StringIO()
    with redirect_stdout(f):
        candidate('','')
    out = f.getvalue().strip('\n')

    assert "3" == out
    for i in range(0, 10):
        if i != 3:
            assert str(i) != out

if __name__ == '__main__':
    check(reverse_delete)
