#include <iostream>
using namespace std;
int step(int i,int j)
{
if(i == 0 && j == 0) return 0;
if(i == 0 && j != 0) return 1;
if(i != 0 && j == 0) return 1;
if(i != 0 && j != 0) return step(i - 1,j) + step(i,j - 1);
}
int main()
{
int i,j;
cin >> i >> j;
cout << step(i,j) << endl;
return 0;
}