program sum;
{$APPTYPE CONSOLE}
uses SysUtils;
var N, i, s: integer;
begin
    write('sum [1..N] Program. Please Enter N: ');
    readln(N);
    s := 0;
    i := 1;
    while i <= N do begin
        s := s + i;
        i := i + 1;
    end;
    writeln('sum[1..N] = ', s:8);
    readln
end.