1=-1+1/2+(-1/2)+1/3+(-1/3)+.+1/9+(-1/9)+1/10+(-1/10)
=(1/2-1)+(1/3-1/2)+(1/4-1/3)+.+(1/10-1/9)
=-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90-1/10
1=-1+1/2+(-1/2)+1/3+(-1/3)+.+1/9+(-1/9)+1/10+(-1/10)
=(1/2-1)+(1/3-1/2)+(1/4-1/3)+.+(1/10-1/9)
=-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90-1/10