$\displaystyle \int_{-\infty}^{-1} e^{-26t}dt$

This is my work:

$\displaystyle \lim_{a \rightarrow -\infty}\int_{a}^{-1} e^{-26t}=\lim_{a \rightarrow -\infty}\left[-\frac{1}{26}e^{-26t}\right]_a^{-1}=\lim_{a \rightarrow -\infty}\left[-\frac{1}{26}\left(e^{26}-e^{-26a}\right)\right]$

$\displaystyle \lim_{a \rightarrow -\infty}e^x =0$ so it would converge to $\displaystyle -\frac{1}{26}e^{26}$ but that's not the correct answer. Can someone explain to me where I went wrong?