Fixed Points

An index of an array is called a fixed point if the value on the index of the array is equal to the index itself. Formally, an index $i$ of an array $A$ of length $N$ is a fixed point if $A_i = i$, where $1\leq i \leq N$. For example, in the array $A = [1, 3, 3, 4, 1]$, the indices $1, 3, 4$ are fixed points. Chef has an array $A$ consisting of $N$ integers. Chef tries to find the number of fix