ABC agreed to set up a retirement plan for its employees: 1. Annual contribution to a fund managed by a trustee, 400,000 every year 2. Upon retirement, an employee shall receive retirement benefit based on whatever amount is accumulated on the fund 3. Actual contribution to the fund are: 160,000 on 2021, 250,000 on 2022, and 600,000 on 2023. What is the total liability on the retirement fund of AMM Inc. as of December 31, 2023?