Rafael, who is 40, earns $30,000 in 2024. Although he can contribute up to $7,000 to his traditional IRA for 2024, he contributes only $3,000. On May 3, 2025, Rafael decided to make up the difference between his actual contributions for 2024 and his 2024 limit. What amount of the difference can he contribute to his traditional IRA for the previous year (2024)?