How to count the number of times the basic operation executes? (code)

public class GCDD {

public static void main(String[] args) { System.out.println("The gcd is " + gcd(1000, 30)); }

public static int gcd(int num1, int num2) { if (num2 == 0) return num1; else return gcd(num2, num1 % num2); } }