pascal对给定的整数n(1大于等于n小于等于100）,求下列式值.

var
i,j,n:integer;
ans:longint;
sum:array[0..101] of integer;
begin
read(n);
fillchar(sum,sizeof(sum),0);
for i:=1 to n do
sum[i]:=sum[i-1]+i;
sum:=0
for i:=1 to n do
ans:=ans+sum[i];
write(ans);
end.