TONG PASCAL

var n,s:longint; 
begin
    assign(input, 'TONG.inp');reset(input);
    assign(output, 'TONG.out');rewrite(output);
    readln(n);
    s:=n*(n+1) div 2;
    writeln('Tong tu 1 den ',n,' la ',s);
end.