#include <fstream>
using namespace std;
ifstream fin ("pascal.in");
ofstream fout ("pascal.out");
int k,t,i,j,n,a[100][100],nn,kk;

int main()
{

    fin>>nn>>kk;
    for(i=0; i<=nn; i++)
        for(j=0; j<=i; j++)
            if(j==0)
                a[i][j]=1;
            else a[i][j]=a[i-1][j]+a[i-1][j-1];

    /*for(k=0; k<=nn; k++)
    {
        for(t=0; t<k+1; t++)
            fout<<a[k][t]<<" ";
        fout<<endl;
    }*/


    //fout<<endl<<a[nn][kk];
    fout<<a[nn][kk];
}