Table:
text: 2004 NCAA Division I Men's Swimming and Diving Championships
Medal table
Medal table
Rank_ Institution Gold Silver Bronze
14 University of Kentucky 0 0 1
Total Total 21 21 21

text: 2004 NCAA Division I Men's Swimming and Diving Championships
Medal table
Medal table
Rank_ Institution Gold Silver Bronze
1 University of Texas at Austin 7 2 1
2 Auburn University 5 3 4
3 University of Michigan 3 2 0
4 Stanford University 2 5 3
5 University of Southern California 1 2 0
6 University of Florida 1 0 2
7 University of Tennessee 1 1 0
8 Arizona State University 1 0 1
9 University of California, Berkeley 0 3 2
10 University of Arizona 0 1 3
11 University of South Carolina 0 1 1
11 University of Wyoming 0 1 1
13 University of Georgia 0 0 2

Question: What is the lowest number of silver medals for teams with 21+ gold and 4+ bronze medals in the 2004 NCAA Division I Men's Swimming and Diving Championships?