data acid;
  input id  v1-v4;
cards;
1 39.8  38.0  22.2  23.2
2 53.7  37.2  18.7  18.5
3 47.3  39.8  23.3  22.1
4 41.7  37.6  22.8  22.3
5 44.7  38.5  24.8  24.4
6 47.9  39.8  22.0  23.3
run;
proc cluster method=single outtree=tree;
id id;
run;