The main idea of the news is ______.

North Korea has signed an agreement in principle to abandon its existing nuclear weapons and other nuclear weapons in return for energy and security guarantees from its neighbors and the United States. North Korea also pledged to return soon to the Nuclear Non-Proliferation Treaty. But it restated its rights to peaceful uses of nuclear power. Charles G. reports from Seoul,
     It’s the first sign of progress after three years of confrontation, the statement of principles that would rid the Korean Peninsula of nuclear weapons. The North said it would abandon its nuclear programs in return for aid, economic cooperation and security guarantees. The chief American negotiator Christopher Hill described it as "a win-win situation" and "a good agreement for every one". The most contentious disputes between North Korea and Washington have all been deferred for future discussions. North Korea continues to insist on the provision of a civilian nuclear power plant to replace its existing facilities. The demand had nearly led to the breakdown of the talks.