How to decrypt a swf?

programming flash
1

I have a file swf encryted. This is what I get with Sothink 6.3

var \x01 = 708;
for (\x01 = eval("\x01") - 218; eval("\x01") == 490; \x01 = eval("\x01") + 229)
{
    \x01 = eval("\x01") - 343;
    if (false)
    {
        continue;
    } // end if
} // end of for
if (eval("\x01") == 147)
{
    \x01 = eval("\x01") + 229;
   
   
} // end if
\x01 = eval("\x01") + 124;
if (eval("\x01") == 500)
{
    \x01 = eval("\x01") + 109;
    if (false)

Please help me decryt it