Affect or effect?

Affect of effect?
If following sentence, which one should be used?

In case either party shall breach or default in the effective performance of any terms, conditions, covenants, or agreements contained in this Agreement, the other party may give to such breaching or defaulting party a written notice of such default, and if such breaching or defaulting party does not effect an adequate cure thereof within 10 days of grace period or upon such later date specified in the notice.