Revision history of "discard until start of last substring" (Z11422)
ᡳᠯᡤᠠᠪᡠᠨ ᠰᠣᠨᠵᠣᡥᠣᠨ᠄ ᠪᡠᡳᠪᡠᠯᡝᡵᡝ ᡩᡠᡵᡠᠨ ᡳ ᡵᠠᡩᡳᠣ ᡴᡠᠸᠠᠩᠰᡝ ᠪᡝ ᠰᠣᠨᠵᠣᡥᠣ ᠮᠠᠩᡤᡳ ᡝᠨᡨᡝᡵ ᡝᡳᠴᡳ ᡝᠨᡨᡝᡵ ᡶᡝᠵᡝᡵᡤᡳ ᠪᡝ ᠠᠨᠠ᠈
ᠰᡠᡥᡝ ᡤᡳᠰᡠᠨ᠄ (ᠨᡝ) = ᡥᠠᠨᠴᡳᡴᡳ ᡩᡠᡵᡠᠨ ᠴᡳ ᡩᡠᡳᠪᡠᠯᡝᠮᠪᡳ᠈ (ᡝᠪᡳᠰᡳᡥᡝ) = ᠨᡝᠨᡝᡥᡝ ᡩᡠᡵᡠᠨ ᠴᡳ ᡩᡠᡳᠪᡠᠯᡝᠮᠪᡳ᠈ m = ᠠᠵᡳᡤᡝ ᡴᡡᠪᡠᠯᡳᠨ᠈