算法训练 未名湖边的烦恼

import java.util.Scanner;
public class Main {
    static int f(int n,int m){
        if(n<m)
            return 0;
        if(m==0)
            return 1;
        return f(n,m-1)+f(n-1,m);
            
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc=new Scanner(System.in);
        System.out.println(f(sc.nextInt(),sc.nextInt()));
    }

}