Importing data to Dynamics 365 online

Hi,

I want to import data from excel sheets to Contract entity and Contact entity. The issue is when I tried to import data first to Contact entity its fails because its looking for existing name from Contact entity. Then when i m tried to import data to Contact entity first its also fails because its looking for existing Contract Name from the Contract entity.

I have a N:1 relationship between Contact and Contract entity.

Can someone please tell me how can I resolved this issue.

Thanks.