#include<fstream>
using namespace std;
ifstream fin ("date.in");
ofstream fout ("date.out");

int main()
{
    unsigned long int a[500][500]={0};
    int i,j,m,n;
    fin>>n>>m;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            if(i==1 || j==1) a[i][j]=1;
            else a[i][j]=a[i-1][j]+a[i][j-1];

    fout<<a[n][m]<<endl;
    fin.close();
    fout.close();
    return 0;
}