#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int INF = (int) 1e9 + 1e6 + 123;
const ll LINF = (ll) 1e18 + 1e9 + 123;
#define rep(i, s, t) for (auto i = (s); i < (t); ++(i))
#define per(i, s, t) for (auto i = (s); i >= (t); --(i))
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define mp make_pair
#define pb push_back
bool mini(auto &x, const auto &y) {
if (y < x) {
x = y;
return 1;
}
return 0;
}
bool maxi(auto &x, const auto &y) {
if (y > x) {
x = y;
return 1;
}
return 0;
}
void run();
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
run();
return 0;
}
const int N = 15;
const ll MOD = (ll) 1e9 + 7;
ll fact[N], rfact[N];
ll power(ll x, ll y) {
if (y == 0) {
return 1;
}
if (y % 2 == 0) {
ll t = power(x, y / 2);
return t * t % MOD;
} else {
return power(x, y - 1) * x % MOD;
}
}
ll dp[N][N];
void add(ll &x, ll y) {
x += y;
x %= MOD;
}
ll cnk(int n, int k) {
return fact[n] * rfact[n - k] % MOD * rfact[k] % MOD;
}
void run() {
fact[0] = 1;
rep(i, 1, N) {
fact[i] = fact[i - 1] * i % MOD;
}
rep(i, 0, N) {
rfact[i] = power(fact[i], MOD - 2);
}
dp[0][0] = 1;
rep(n, 1, N) {
rep(k, 0, n) {
add(dp[n][k], dp[n - 1][k]);
if (k > 0) {
add(dp[n][k], dp[n - 1][k - 1] * (n - k) % MOD);
}
add(dp[n][k], dp[n - 1][k] * k % MOD);
}
}
int n, k;
cin >> n >> k;
cout << dp[n][k - 1] << "\n";
}
