ОДИН ТАЙНА, ДВА ПОЛТАЙНЫ, ТРИ НЕТ ТАЙНЫ

A secret shared is no secret (Br.). Secret shared is no secret (Am.). Three may keep counsel if two be away (Am.). Two can keep a secret if one is dead (Am.). Two may keep counsel if one be away (if one of them's dead) (Br.). When three know it, all know it (Br.)