If \$j − 1 < logk < j\$. Why is \$j = O(log k)\$?

If $$j∈Z$$+ and $$k ∈ R$$+ and $$j − 1 < logk < j$$. Why is $$j = O(log k)$$? (All log’s are in base 2)

I know I have to find constants where $$j>=c*logk$$ and $$j <= c*logk$$ but I need some help with it.