You are a helpful assistant in structing the unstructure json into structured json. Think in a step by step manner.
Unstructured JSON:

{"Letter No":{"0":"NHSRCL#OHQ97\n5","1":"L&T#001","2":null,"3":null,"4":null,"5":null,"6":null,"7":null,"8":null,"9":null,"10":null,"11":null,"12":null,"13":null,"14":null,"15":null,"16":null,"17":null,"18":null,"19":null,"20":null,"21":null,"22":null,"23":null,"24":null,"25":null,"26":null,"27":null,"28":null,"29":null,"30":null,"31":null},"Date":{"0":"28-Oct-20","1":"22-Sep-20","2":null,"3":null,"4":null,"5":null,"6":null,"7":null,"8":null,"9":null,"10":null,"11":null,"12":null,"13":null,"14":null,"15":null,"16":null,"17":null,"18":null,"19":null,"20":null,"21":null,"22":null,"23":null,"24":null,"25":null,"26":null,"27":null,"28":null,"29":null,"30":null,"31":null},"Gist":{"0":"The Contractor planned execution programme submitted along\nwith its Technical Bid dated 22 September 2020 is referred, that\npresents the Contractor\u2019s consideration on the planned\ntimelines of handing over of stretches, among other things.\nSuch a Technical Bid was accepted by the Employer and the\nContractor was awarded the LOA on 28 October 2020.","1":"Project length of 237.10 Km was divided into 29 stretches. For\neach stretch of the Project, date for access to and possession\nof the site was mentioned vide the activity namely \u2018Handing\nOver of ROW\u2019. The planned handing over dates considered by\nthe Contractor for various stretches is put below:","2":null,"3":null,"4":null,"5":null,"6":null,"7":null,"8":null,"9":null,"10":null,"11":null,"12":null,"13":null,"14":null,"15":null,"16":null,"17":null,"18":null,"19":null,"20":null,"21":null,"22":null,"23":null,"24":null,"25":null,"26":null,"27":null,"28":null,"29":null,"30":null,"31":null},"Unnamed: 3":{"0":null,"1":null,"2":"Sl. No.","3":null,"4":"1","5":"2","6":"3","7":"4","8":"5","9":"6","10":"7","11":"8","12":"9","13":"10","14":"11","15":"12","16":"13","17":"14","18":"15","19":"16","20":"17","21":"18","22":"19","23":"20","24":"21","25":"22","26":"23","27":"24","28":"25","29":"26","30":"27","31":"28"},"Unnamed: 4":{"0":null,"1":null,"2":"Chainage","3":"From","4":"156.600","5":"159.770","6":"166.000","7":"188.000","8":"209.000","9":"210.485","10":"217.960","11":"224.000","12":"235.000","13":"247.000","14":"255.060","15":"258.500","16":"265.142","17":"265.500","18":"276.660","19":"287.000","20":"297.287","21":"306.500","22":"317.447","23":"321.581","24":"326.522","25":"327.002","26":"328.000","27":"333.606","28":"336.800","29":"345.000","30":"365.500","31":"376.800"},"Unnamed: 5":{"0":null,"1":null,"2":null,"3":"To","4":"159.670","5":"166.000","6":"188.000","7":"209.000","8":"210.275","9":"217.960","10":"224.000","11":"235.000","12":"247.000","13":"255.060","14":"258.500","15":"265.142","16":"265.500","17":"275.940","18":"287.000","19":"297.027","20":"306.500","21":"317.347","22":"321.581","23":"326.522","24":"326.772","25":"328.000","26":"333.276","27":"336.800","28":"345.000","29":"365.500","30":"376.800","31":"384.941"},"Unnamed: 6":{"0":null,"1":null,"2":"End Date of\nHanding\nOver as per\nBid\nProgramme","3":null,"4":"14-Jul-2021","5":"01-Jun-2021","6":"31-Jan-2021","7":"01-Jun-2021","8":"01-Jun-2021","9":"01-Jun-2021","10":"03-Jan-2021","11":"03-Jan-2021","12":"03-Jan-2021","13":"03-Jan-2021","14":"03-Jan-2021","15":"03-Jan-2021","16":"03-Jan-2021","17":"01-Jun-2021","18":"01-Jun-2021","19":"01-Jun-2021","20":"14-Jul-2021","21":"14-Jul-2021","22":"01-Jun-2021","23":"31-Jan-2021","24":"31-Jan-2021","25":"01-Jun-2021","26":"31-Jan-2021","27":"01-Jun-2021","28":"1-Jan-2021","29":"03-Jan-2021","30":"31-Jan-2021","31":"31-Jan-2021"}}