Analyze the time complexity of this program in big-O notation, assuming that the total number of numbers and symbols in the expression is n. Expect any type of numbers including integers, floats/doubles

static double evalPostFix() { Stack s = new Stack(); String token; Double a, b, result=0.0; boolean isNumber;

Scanner sc = new Scanner(System.in); token = sc.next(); while (token.charAt(0) != '=') { try { isNumber = true; result = Double.parseDouble(token); } catch (Exception e) { isNumber = false; } if (isNumber) s.push(result); else { switch (token.charAt(0)) { case +: a = s.pop(); b = s.pop(); s.push(a+b); break; case -: a = s.pop(); b = s.pop(); s.push(a-b); break; case *: a = s.pop(); b = s.pop(); s.push(a*b); break; case /: a = s.pop(); b = s.pop(); s.push(a/b); break; case ^: a = s.pop(); b = s.pop(); s.push(Math.exp(a*Math.log(b))); break; } }

token = sc.next(); } return s.peek(); }