program TinhTong;
var
  m, n, tong: integer;

function TinhTongSoNguyen(m, n: integer): integer;
var
  i: integer;
begin
  TinhTongSoNguyen := 0;
  for i := m to n do
  begin
    TinhTongSoNguyen := TinhTongSoNguyen + i;
  end;
end;

begin
  writeln('Nhap vao hai so nguyen m va n (m < n): ');
  readln(m, n);
  
  tong := TinhTongSoNguyen(m, n);
  
  writeln('Tong cac so nguyen tu ', m, ' den ', n, ' la: ', tong);
  
  readln;
end.