记录Java递归调用的数量（查找GCD）

Question

对于该递归Java程序，我无法在我的课程中匹配相同的输出。对于整数76和84，递归调用的数量应为3，但我得到的是4。我的教授的样本输出是否错误？

package Week13;

import java.util.Scanner;

public class Assignment12_Part1 {
    static int counter;

    public static void main(String[] args) {
        counter = 0;

        System.out.print("Please enter two integers space seperated: ");
        Scanner input = new Scanner(System.in);
        int a = input.nextInt();
        int b = input.nextInt();
        System.out.println("The GCD of " + a + " and " + b + " is " + gcd(a, b));
        System.out.printf("Total %4d recursive calls", counter);
        input.close();
    }

    public static int gcd(int a, int b) {
        counter++;
        if (b == 0) return a;
        else if (a == 0) return b;
        else if (a % b == 0) return b;
        else return gcd(b, a % b);
    }

}