user: In today's field day challenge, the 4th graders were competing against the 5th graders.  Each grade had 2 different classes.  The first 4th grade class had 12 girls and 13 boys.  The second 4th grade class had 15 girls and 11 boys.  The first 5th grade class had 9 girls and 13 boys while the second 5th grade class had 10 girls and 11 boys.  In total, how many more boys were competing than girls? Let's think step by step and output the final answer after "####".
Answer: 2