Let \(T_{r}\) be the \(r^{\text{th}\text{~}}\) term of an A.P. whose first term is \(a\) and common difference is \(d\). If for some positive integers \(m,n,m \neq n,T_{m} = \frac{1}{n}\), and \(T_{n} = \frac{1}{m}\), then\\ \(a - d\) equals \(a - d\) equals