[{"state":"Jharkhand","district":"Ranchi","salesman":"amit"},{"state":"Jharkhand","district":"Ranchi","salesman":"sumit"},{"state":"Jharkhand","district":"Bokaro","salesman":"rahul"},{"state":"Jharkhand","district":"Bokaro","salesman":"rajesh"},{"state":"Jharkhand","district":"Bokaro","salesman":"ravi"},{"state":"Orisha","district":"Puri","salesman":"anish"},{"state":"Orisha","district":"Puri","salesman":"arjun"},{"state":"Orisha","district":"Puri","salesman":"aryan"},{"state":"Orisha","district":"Bhubneswar","salesman":"anuj"},{"state":"Orisha","district":"Bhubneswar","salesman":"chandan"},{"state":"Orisha","district":"Bhubneswar","salesman":"charan"}]

db.collection.aggregate([{$group:{_id:{state:"$state",district:"$district",salesman:"$salesman"},sum:{$sum:1}}},{$group:{_id:{state:"$_id.state",district:"$_id.district",},salesmen:{$push:{salesmen:"$_id.salesman",count:"$sum"}},count:{$sum:"$sum"}}},{$group:{_id:"$_id.state",districts:{$push:{district:"$_id.district",salesmen:"$salesmen",count:"$count"}},count:{$sum:"$count"}}}])