IGST INPUT TAX wrongly claimed in 3B may 2018

we have submitted 3b for may 2018 in which
in the month may 2018 in 3B return has entered in col 4 ( A)5 in col eligible ITC wrongly entered purchases amount of Rs 717800 instead of tax @ 5% Rs 35890 resulting to excess claim of input tax and ledger credited for Rs 681910 mistake now identified he has filled GSTR1and GSTR 3B UPDATE .kindly guide how to proceed for reversal of in put tax while submitting 3B for October 2018 if so what is intrest rate to be payable please enlighten