Challenge

Server: nc 34.85.45.159 20005
File: task.py

Solution

The challenge is broken :(

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R = self.recvpoint(30)
(u,v) = R
print R
if (u*v)%p == 0:
    self.dosend("%s\n" % FLAG)

where the input function recvpoint(sz):

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def recvpoint(self, sz):
    try:
        ...
    except:
        res = ''
        x = 0
        y = 0
    return (x,y)

So just send some garbage to get the flag.

*ctf{2ca55eb39e6fd9e5f1e7396b5c24a352}