Java再帰求後の1つの数は前の2つの数の和です

package javaTest;

public class test {
	
	public static void main(String[] arge){
		int cout=0,a1=0,a2=1,cc=0;
		test t= new test();
		cc=t.sum(cout,a1,a2);
		System.out.println(cc);
	}	
	public int sum(int cout,int a1,int a2){
		cout++;
		if(cout>30)  //   30   
			return a1;
		else
			return sum(cout,a2,a1+a2);
	}
}