* Atomic Mass Unit (amu): An atomic mass unit is defined as 1/12th the mass of a carbon-12 atom. It's a way to measure the mass of atoms and molecules.

* Hydrogen: A hydrogen atom has a mass of approximately 1 amu.

Therefore, 1 atomic mass unit of hydrogen contains approximately 1 hydrogen atom.

However, it's important to note that this is an approximation. The actual mass of a hydrogen atom is slightly less than 1 amu.