IPv6

In IPv6, the next generation of the Internet protocol, an IP address is 128 bits long. The full text representation of an IPv6 address consists of 8 groups of 4 hexadecimal digits each, where groups are separated by colon characters ':'. For example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
To compress this textual representation, we are allowed the following transformations:
• All or some leading zeroes in a group can be removed. For example, the above address can be simplified as: 2001:db8:85a3:0:00:8a2e:370:7334
• Additionally, one or more consecutive groups of zeroes can be replaced by adouble colon "::". The above address becomes: 2001:db8:85a3::8a2e:370:7334 This last simplification can be done only once so that the resulting text representation is never ambiguous. Write a program that takes a valid(possibly compressed) text representation of an IPv6 address and outputs its full text representation.