\[\boxed{\text{466\ (466).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\sqrt{1 + \sqrt{2 + \sqrt{x}}} = 2\]
\[\left( \sqrt{1 + \sqrt{2 + \sqrt{x}}} \right)^{2} = 2^{2}\]
\[1 + \sqrt{2 + \sqrt{x}} = 4\]
\[\sqrt{2 + \sqrt{x}} = 4 - 1\]
\[\sqrt{2 + \sqrt{x}} = 3\]
\[\left( \sqrt{2 + \sqrt{x}} \right)^{2} = 3^{2}\]
\[2 + \sqrt{x} = 9\]
\[\sqrt{x} = 9 - 2\]
\[\sqrt{x} = 7\]
\[\left( \sqrt{x} \right)^{2} = 7^{2}\]
\[x = 49.\]
\[Ответ:x = 49.\]