走方格的方案数

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String arr[];
        int n,m;
        while (in.hasNext()) { 
            String s = in.nextLine();
            arr = s.split(" ");
            n = Integer.parseInt(arr[0]);
            m = Integer.parseInt(arr[1]);
            System.out.println(getStep(n,m));
        }
    }
    public static int getStep(int n,int m){
        if(n == 0 || m == 0){ //递归终止条件
            return 1;
        }
        return getStep(n-1,m)+getStep(n,m-1); //递归通式
    }
}