A left ceiling bracket delimiter that rounds a number or expression upward to the nearest integer.
Examples
Ceiling function (next highest integer)
\lceil 3.14 \rceil = 4
Number of groups needed
\text{Groups needed} = \left\lceil \frac{n}{k} \right\rceil
Logarithmic complexity bound
\text{Time} = \left\lceil \log_2(n) \right\rceil