Given a single positive integer x, we will write an expression of the form x (op1) x (op2) x (op3) x ... where each operator op1, op2, etc. is either addition, subtraction, multiplication, or division (+, -, *, or /). For example, with x = 3, we might write 3 * 3 / 3 + 3 - 3 which is a value of 3. When writing such an expression, we adhere to the following conventions: We would like to write an expression with the least number of operators such that the expression equals the given target. Return the least number of operators used.