Subsequence Sort

Chef has an array $A$ containing $N$ non-negative integers. He will perform a sequence of operations on this array. The $X$-th operation is as follows: - For each index $i$ ($1 \leq i \leq N$), either leave $A_i$ unchanged, or replace $A_i$ with $A_i \mid X$. The choice is made independently for each index. Here, $\mid$ denotes the bitwise OR operation. Find the minimum number of opera