A mobile equipment identifier (MEID) is a globally unique number identifying a physical piece of CDMA2000 mobile station equipment. The number format is defined by the 3GPP2 report S.R0048 but in practical terms, it can be seen as an IMEI but with hexadecimal digits.

An MEID is 56 bits long (14 hexadecimal digits). It consists of three fields, including an 8-bit regional code (RR), a 24-bit manufacturer code, and a 24-bit manufacturer-assigned serial number. The check digit (CD) is not considered part of the MEID.

The MEID was created to replace ESNs, whose virgin form was exhausted in November 2008. As of TIA/EIA/IS-41 Revision D and TIA/EIA/IS-2000 Rev C, the ESN is still a required field in many messages—for compatibility, devices with an MEID can use a pseudo-ESN (pESN), which is a manufacturer code of 0x80 (formerly reserved) followed by the least significant 24 bits of the SHA-1 hash of the MEID.MEIDs are used on CDMA mobile phones. GSM phones do not have ESN or MIN, only an International Mobile Station Equipment Identity (IMEI) number.

Your task is change MEID to R31337133713373. you can verify your flag at http://ctf.hpandro.raviramesh.info