Find Number From Factorial

A factorial of a non-negative integer is defined as the product of all numbers from $1$ to $N$ inclusive. The factorial of $N$ is denoted by $N!$. By convention, $0! = 1$. For example, $5! = 5 \times 4 \times 3 \times 2 \times 1 = 120$. Your task is simple. You are given $N!$, where you have to find $N$. If multiple values exist for a single factorial, find the largest one. It is guara