find power of the signal
Since this is clearly homework, and the limits on the $\sum$ are crucial to figuring out whether there's an answer:

Hint: Parseval's Theorem states that power in time domain is equivalent to power in frequency domain. What is the power in $x(t)$? Is $x(t)$ periodic? If so, what's the period?

As usual, it often helps to make a drawing (that's, by the way, the minimum I'd have expected from your question!) to get a feeling for the signal you're dealing with.