#include <bits/stdc++.h>

using namespace std;

ifstream f("perm.in");
ofstream g("perm.out");

void adaug(short int A[], short int B[])
{
    short int i,T=0;

    A[0]=max(A[0],B[0]);
    for(i=1; i<=A[0]; ++i)
    {
        A[i]+=B[i]+T;
        T=A[i]/10;
        A[i]%=10;
    }

    if(T) A[++A[0]]=T;
}

void mult(short int H[], short int X, short int nh[])
{
    short int i,T=0;
    nh[0]=H[0];
    for(i=1; i<=H[0]; ++i)
    {
        nh[i]=H[i]*X+T;
        T=nh[i]/10;
        nh[i]=nh[i]%10;
    }
    while (T)
    {
        nh[++nh[0]]=T%10;
        T/=10;
    }
}

short int n,k,i,j,d[210][210][510];
int main()
{
    f>>n>>k;
    d[1][1][0]=1;
    d[1][1][1]=1;

    for(i=2; i<=n; ++i)
    {
        for(j=1; j<=min(i,k); ++j)
        {
            mult(d[i-1][j],i-1,d[i][j]);
            adaug(d[i][j],d[i-1][j-1]);
        }
    }

    for(i=d[n][k][0]; i>=1; --i)g<<d[n][k][i];
    return 0;
}