Farmer James has three types of cows on his farm. A cow with zero legs is called a <spanclass=′latex−italic′>groundbeef</span>, a cow with one leg is called a <spanclass=′latex−italic′>steak</span>, and a cow with two legs is called a <spanclass=′latex−italic′>leanbeef</span>. Farmer James counts a total of 20 cows and 18 legs on his farm. How many more <spanclass=′latex−italic′>groundbeef</span>s than <spanclass=′latex−italic′>leanbeef</span>s does Farmer James have?Proposed by James Lin