Valid Expression

The correct way of evaluating an expression with $*, +,$ and $-$ is, first multiplication, then addition, and then subtraction. For example, the expression $2+3*7-5 = 2+21-5 = 23-5 = 18$. You are given integers $N$ and $X$. Your task is to generate a string $S$ of length $N$ consisting **only** of $*, +,$ and $-$ such that when these $N$ operators are placed in order between $(N+1)$ **ones**, the