What Happened to the Soviets in Afghanistan?

The sour revolution took place on april 20 eighth, 19 78. And was not very long after december 19 79 that the soviet army crossed the oxus river into afghanistan. And that invasion, of course, was a total disaster. But why did they change their mind? Then we still don't have the answer. I mean, some one does, but the military archives, despite all the changes, are very heavily guarded. What i am told what happened was this, that when afise laman killed the president of the country and seized power within the pidipie andn he became the supreme ruler of anestan. There were people in o who said