QQ\u0051 (C99)\U000051 (C99)\x51 (encoding-dependent)\121 (encoding-dependent)\u{51} (C++23)\x{51} (C++23, encoding-dependent)\o{121} (C++23, encoding-dependent)\U00000051\u0051\x51 (encoding-dependent)\121 (encoding-dependent)\u0051\u{51}\u0051\x51\51\000051=51%51