( m == 0 ? "no child have a common prefix" :
( m == 1 ? "selected child have exactly this key" :
( m == 2 ? "selected child constitutes a prefix" :
( m == 0 ? "no child have a common prefix" :
( m == 1 ? "selected child have exactly this key" :
( m == 2 ? "selected child constitutes a prefix" :