Chemistry Stoichiometry

Question: 

N\(_2\) + 3 H\(_2\) \(\longrightarrow\) 2 NH\(_3\)

How many grams of hydrogen are needed to produce 68 g of ammonia? (molar mass of NH\(_3\) = 12.031 g/mol, the molar mass of H\(_2\) = 2.015 g/mol)