Get Relationship Name between Parent And Child Object Salesforce

String parentObj = 'Account';
String childObj = 'Contact';

Map<String,Schema.SObjectField> fieldMap = Schema.getGlobalDescribe().get(childObj).getDescribe().fields.getMap();
for(Schema.SObjectField f:fieldMap.values()){
   String type = String.valueOf(f.getDescribe().getReferenceTo());
   if(type.contains(parentObj)){
       system.debug('Field Name:- ' + f.getDescribe().getName());
   }
}