在等差数列{an}中，a1=﹣9，S3=S7，则当前n项和Sn最小时，n=____
— I feel and sleepy.
— Why not to have a rest?
若方程x2+y2﹣x+y+m=0表示圆，则实数m的取值范围是（ ）
I was ____ tired ____ I went to sleep early.
