return me the number of researchers in " University of Michigan " .
SELECT COUNT ( DISTINCT t1.name ) FROM organization AS t2 JOIN author AS t1 ON t2.oid  =  t1.oid WHERE t2.name  =  "University of Michigan";
SELECT COUNT ( DISTINCT t1.name ) FROM organization AS t2 JOIN author AS t1 ON t2.oid  =  t1.oid WHERE t2.name  =  "University of Michigan";
[{'COUNT ( DISTINCT t1.name )': 0}]