Permutation Disturbance

Chef likes to create disturbance in numbers. In other words, he does not like when numbers are in their right positions. He has a permutation $P$ of size $N$. In one operation, he can swap any two **adjacent** elements. His goal is to alter the permutation in such a way that $P_i \neq i$ satisfies for all $1 \le i \le N$. Help Chef find the **minimum** number of operations required to reach hi