#include <iostream>
#include <fstream>

using namespace std;

#define Nmax 202

uint64_t S[Nmax][Nmax];

int N, K;

void gen()
{
    S[1][1] = 1;

    for ( int i = 2; i < Nmax; ++i )
            for ( int j = 1; j <= i; ++j )
                    S[i][j] = ( S[i - 1][j - 1] - ( i - 1 ) * S[i - 1][j] );
}

int main()
{
    ifstream f("permutari.in");
    ofstream g("permutari.out");

    f >> N >> K;

    gen();

    g << S[N][K] << "\n";

    f.close();
    g.close();

    return 0;
}