This is the 220th most frequent Korean word.
대통령과
"대통령과" means "with the president" in English.
Here, "대통령과" is used to indicate that the meeting involves or is attended by the president, using "과" to mean "with" and establishing a relationship of accompaniment.
대통령과 함께 회의가 시작되었습니다.
The meeting started with the president.
In this context, "대통령과의" shows possession or relation, indicating that the interview is with the president, using "과" with the possessive particle "의".
내일은 대통령과의 인터뷰가 예정되어 있습니다.
An interview with the president is scheduled for tomorrow.
Here, "대통령과" connects "the president" and "the assembly members," using "과" to list joined items in a compound subject.