How to get all Child Relationship Names related to Parent Object using Apex

gistfile1.txt

String parentObjectName = 'Account';  
Map<string,string> objectRelationshipMap = new Map<string,string>();
Map<String, Schema.SObjectType> schemaMap = Schema.getGlobalDescribe();
for(String ss1: schemaMap.keyset()){
    Schema.SObjectType objToken=schemaMap.get(ss1);
    if(ss1.equalsignorecase(parentObjectName)){
        //find details about sobject
        Schema.DescribeSObjectResult objDescribe=objToken.getdescribe();
        List<Schema.ChildRelationship> childRelationshipList = objDescribe.getChildRelationships();
        system.debug('******childRelationshipList.size():'+childRelationshipList.size());
        for(Schema.ChildRelationship ss:childRelationshipList){
            string RelationshipName=ss.getRelationshipName();
			string childObjectName = string.valueof(ss.getChildSObject());
			string childFieldToken = string.valueof(ss.getField());
			system.debug('*********childFieldToken:'+ childFieldToken);
			system.debug('*********childObjectName:'+childObjectName); 
			system.debug('*********RelationshipName:'+RelationshipName);
			objectRelationshipMap.put(childObjectName+'.'+childFieldToken,RelationshipName);
        }
    }
}
system.debug('***objectRelationshipMap.size():'+objectRelationshipMap.size());
system.debug('***objectRelationshipMap:'+objectRelationshipMap);