Applications of Logarithms

The pH of a substance represents the basicity or acidity of a substance. It is calculated by taking the $\mathrm{-log[H^+]}.\;[H^+]\;$is the concentration of hydrogen ions in the substance. If Buttermilk has an approximate hydrogen ion concentration of $2.5\times 10^{-5}$, what is the pH of Buttermilk?