#include<bits/stdc++.h>
using namespace std;

int a[1010][1010];
int n,m; 

int main(){
	cin>>n>>m;
	a[1][1] = 1;
	for(int i = 1;i <= n;i++){
		for(int j = 1;j <= m;j++){
			if(i==1&&j==1) continue;
			else a[i][j] = a[i-1][j] + a[i][j-1];
		}
	}
	cout<<a[n][m];
	
    return 0;
}