#pragma GCC optimize("O3")
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")	
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping") 
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#pragma GCC optimize("Ofast")

#include <bits/stdc++.h>

using namespace std;

long long int f[16];
long long int a[16][16];
long long int res[16][16];
long long int temp[16];

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n,m;

    cin >> n >> m;

    if(n < m)
    {
        cout << 0 << '\n';
        return 0;
    }

    f[0] = 1;
    for(int i=1;i<=15;i++)
    {
        f[i] = f[i-1]*i;
    }

    a[1][1] = 1;

    for(int i=2;i<=15;i++)
    {
        for(int j=0;j<i;j++)
        {
            a[i][j+1] += a[i-1][j];
            a[i][j] -= ((i-1)*a[i-1][j]);
        }
    }

    res[n][n] = f[n];
    for(int i=0;i<=n;i++)
    {
        temp[i] = a[n][i];
    }

    for(int i=n-1;i>0;i--)
    {
        res[n][i] = -temp[i]*f[i];
        for(int j=0;j<=i;j++)
        {
            temp[j] += (a[i][j]*(res[n][i]/f[i]));
        }
    }
    
    cout << res[n][m] << '\n';

    return 0;
}