\( 2.5 \, \text{g} \) of protein containing only glycine \( \left( \mathrm{C_2H_5NO_2} \right) \) is dissolved in water to make \( 500 \, \text{mL} \) of solution. The osmotic pressure of this solution at \( 300 \, \mathrm{K} \) is found to be \( 5.03 \times 10^{-3} \, \text{bar} \). The total number of glycine units present in the protein is _______________.
(Given : \( R = 0.083 \, \text{L bar K}^{-1} \, \text{mol}^{-1} \) )