# What is *decimal prefix*?

**Decimal Prefix**(

*also called*:

**Metric Prefix**) is a unit prefix used in the metric system that precedes a basic unit of measure to indicate a decimal multiple or a fraction of that unit.

## Input

**Exa**is a decimal unit prefix in the metric system denoting multiplication by one quintillion (10¹⁸).

## Output

**Atto**is a decimal unit prefix in the metric system denoting division by one quintillion (10¹⁸).