List out the number of students who have the longest duration of absense from school and enlisted in the peace corps.
longest duration of absence refers to MAX(month); peace corps refers to organ = 'peace_corps';
SELECT COUNT(T1.NAME) FROM longest_absense_from_school AS T1 INNER JOIN enlist AS T2 ON T1.name = T2.name WHERE T2.organ = 'peace_corps' ORDER BY T1.month DESC LIMIT 1