Split N

Kulyash is given an integer $N$. His task is to break $N$ into some number of (integer) powers of $2$. TO achieve this, he can perform the following operation several times (possibly, zero): - Choose an integer $X$ which he already has, and break $X$ into $2$ integer parts ($Y$ and $Z$) such that $X = Y + Z$. Find the minimum number of operations required by Kulyash to accomplish his task. ###