guitunes % remove1
coll:               2 3 4 5 6 4 5 6 7 8 9 1 2 3 4 5 6 7
size not changed:   2 3 4 6 4 6 7 8 9 1 2 3 4 6 7 5 6 7
size changed:       2 3 4 6 4 6 7 8 9 1 2 3 4 6 7
<4 removed:         4 6 4 6 7 8 9 4 6 7
guitunes %
