When n = 1, s = (1- 1)/2.
n=2,s =( 1- 1)/2+(2- 1)/2
n=3,s =( 1- 1)/2+(2- 1)/2+(3- 1)/2; ........n=20 15,s=...+(20 15- 1)/2
When n=20 16, S will be output.
Therefore, s = (1-1)/2+(2-1)/2+...+(2015-1)/2.
=( 1+2+3+...+20 14)/2=(
( 1+20 14)*20 14/2
)/2
= 10 14552.5
The final output is S= 10 14552.5.