# What is *length*?

**Length**is a measure of distance. The length of something is the distance between its two ends. Small length is called short and big length is called long. For two or three dimensional things, length is usually the longest side or edge.

## Input

**Meter**is the base unit of length in the International System of Units (SI).

## Output

**Nanometer**is a metric unit of length equal to one-billionth of a meter.